NIMBY isn't really an explanation, unless the underlying local negatives of a building are clear. NIMBY for a wind farm might be based on noise complaints. NIMBY for a nuclear power plant might be based on fear of radiation or an accident. What is NIMBY for microhousing based on?

I suspect existing property owners don't want lots of cheap housing to cut demand and prices for their more conventional properties.

Increasing density also has a lot of downsides for the nearby residents. It means that congested roads become even more congested, and so on. Dirty roads get that much more dirt. Schools become packed such that students end up in temporary trailer buildings instead of classrooms. The problem is that all of these types of infrastructure tend to trail density, and often by many years or even decades. Seattle schools are physically running out of room to house students, causing programs to end and people to get shuffled around.

There are benefits to density as well, as most people who live in a city will attest. But there are certainly compelling disadvantages too, and I think any honest discussion about housing should recognize that residents of an area have a legitimate and fair desire to want their circumstances to stay the same or not get worse. Increasing the density of an area usually entails a lot of quality-of-life disadvantages for the current residents, by straining services and infrastructure, whereas it entails advantages for business owners and business developers and potentially new residents. It also sometimes results in lower housing prices, but the effect of this is not entirely clear (development is virtually never genuinely motivated by the desire to provide low income housing since that's a poor business proposition), and low housing price is not always a priority for residents compared to quality-of-life.

Some of the infrastructure challenges that I'm describing can be fixed over time, but it's by no means a given that it will happen at all: the lower quality of life might just become permanent. Plus shutting down major roads to widen them or increase throughput is a disruptive activity on its own, and is not always possible (where do you get property for a new school?) So major problems can trail increases in density by quite a while. Traffic congestion in particular can become considerably worse because of changes in density, and that takes a very very long time to fix on the scale of city planning.

It's also worth recognizing that people have different values, and so some people might value the increased benefits from further density differently than others, and the increased disadvantages differently. If you purchased a house somewhere that's quiet, safe, and has little traffic, because you keep to yourself and want to raise a family, then you'd be upset if the area around you was transformed into a college dormitory party atmosphere.

I'm not saying that I think there's a clear answer for how to handle city planning problems, but I think we could have better conversations about the problem by recognizing that development and density increases are usually bad for existing residents (those who can afford the area, are happy with the price, and value the quality of life they currently have). It is a conundrum to an extent that many of those current residents would not be there if it were not for previous decisions to increase density in that same city. However, this is only a conundrum on the surface: there is a tipping point where increasing density at first yields tremendous advantages but few disadvantages, and then slowly the disadvantages begin to mount up until they overcome the advantages. I believe many big cities in the US are at this tipping point, such as San Francisco.

Cities are democratic organizations that exist to serve their residents, and so if residents believe that policies are not in their interest, they will vote them down. These zoning questions are ultimately entirely political, just like the question of whether a country should accept Syrian refugees.

Increasing density will increase congestion and overburden infrastructure? That is what you get when you build a place on the premise that everyone owns a private car and should drive everywhere. Density will achieve the opposite in the long-term. In dense, mixed-use places people have the option to go places without driving. The congestion may never leave, but for the people happily walking to their destinations, it won't matter. Picture New York or Tokyo - horrible places to drive, but for most people it doesn't matter because they aren't driving. Walking as a mode of transportation requires practically nothing in the way of infrastructure spending compared to that required for driving. Furthermore, the per-taxpayer-served cost of a street decreases as density increases. If the current residents want to park for free on the street next to their large home, and drive everywhere, and have free parking at all of their destinations, that's great for them, but many people would place more importance on ensuring everyone has access to affordable housing.

San Francisco isn't a good example of the disadvantages of density overcoming the advantages. San Francisco is a good example of the drawbacks of the conversation you call for overwhelming the advantages of that conversation over the course of four or five decades.

> There are benefits to density as well, as most people who live in a city will attest.

Anybody that lives in a city that can attest to the benefits of density? Living in Seattle with kids, can't think of any.

Make a list of the reasons why you live in Seattle and not in rural Wyoming, and you'll have your answer. :)

Typically it's "jobs", followed distantly by everything else, to include things like walkability, cultural attractions, food and dining, ease of visiting friends and family, etc. It varies by person, but the benefits obviously exist or nobody would live in cities.

Maybe none of those are the benefits of density qua density, but they are hard to achieve without the density. (I mean, I would love to live somewhere with a great tech job market, walkable neighborhoods with bars and restaurants, delivery food at 2AM, and where nobody except my friends and I live there. But of course that's impossible. The density is a precondition for everything else.)

You are absolutely right.

We live in Seattle because it was the smallest / least dense city where both me and my wife could find work relevant to our skills. Across the lake, in the Redmond area, there are plenty of jobs and even less density, but we landed in Seattle before we knew any better about the local geography.

The density axis goes from lots-of-breathing-room-but-no-jobs to suffocating-and-jobs-that-barely-afford-a-box, with lots of tradeoff points in the middle. I fail to see how density is a positive in itself, or that more density is a always a net positive.

As for walkability, it is seriously overrated. Most people are not rich enough to live in walking distance of their jobs. If we could make everyone move in walking distance of job, then most likely we wouldn't need density. Next, you get overpriced shops in walking distance. I'll do groceries at Costco, thank you very much. Parks are more likely to come by in less dense areas. The major benefit I see is that one can safely party within walking distance, and even that benefit is eroded by Uber :)

[FWIW, I lived in a couple "walkable" European cities in a previous life. Slogging through cold rain for basic necessities, oh the memories.]

How about being able to walk to places?

Many people argue that putting up micro-housing destroys the "character" of the neighborhood.

I'm not saying it makes sense, but that's the only real argument I've heard.

> What is NIMBY for microhousing based on?

This is an ongoing argument in Northern Virginia (which is not quite as expensive as SF / Seattle / NYC, but probably only one cost tier below that) and the major arguments are basically the same issues that apply to all "just build more housing, stupid" proposals.

Basically, if you suddenly build a lot more housing, you'd start to strain the infrastructure of the community in other ways. That strain is really, really unpleasant to other people who share the infrastructure, and so current residents -- who are often already feeling like things are strained and getting worse over time -- would rather avoid making things worse. The easiest way to avoid making things worse is just to control the number of residents, and the easiest way to do that is to control the amount of housing. If you don't live here, you're probably not using the infrastructure. QED.

In many ways, building more housing is the easiest problem to solve when it comes to urban infrastructure. Providing a heated place out of the rain just isn't that hard, compared to (say) transportation or schools or figuring out sustainable economic balance.

Existing residents are probably (very reasonably) suspicious that once a bunch of tiny apartments are air-dropped in, and then a bunch of people move in to fill them up, that there won't be any solution to any of the knock-on problems that will inevitably result -- parking, traffic, school overcrowding, tax-base changes, stress to physical infrastructure like gas/water/sewer/electric systems -- until those systems become untenably broken. I mean, I can't speak to Seattle, but those things are already an increasingly-severe problem today, with the current number of residents, in my area, and people don't have much faith in government's ability to fix them; so the idea that the situation will be improved once everyone installs a couple of backyard apartments is ridiculous. (And then there are questions like: how are these backyard apartments going to be taxed? Are people who move in really going to pay more in taxes than they consume in services and infrastructure impact, or is this going to externalize costs via taxes on everyone else? There's no clear answer to these questions, and people are reluctant to become the test case.)

If you want more housing, you need more infrastructure. If you want more infrastructure, either you need a very different funding model or you need better government and more trust in that government. Our government is largely (perceived to be) broken, and public infrastructure is (perceived to be) broken or breaking, and so the unsurprising result is that nobody wants to build more housing and add more strain to a system that's well beyond its design capacity anyway.