Why isn't it possible?

More likely it's just not profitable, because most people are only willing to spend so much money paying for parking, and often "downtown" land is quite expensive.

Sometimes it's completely forbidden for zoning reasons.

Sometimes it's a regulatory risk. If the local residents decide they don't want a parking structure, they won't offer you a fair market price to stop it; they'll just try and get city officials to deny or obstruct all the permits you need. (And a large construction project needs a lot of permits in most jurisdictions.)

Sometimes it's just prohibitively expensive to convert. In order to tear down a typical commercial building, you'd have to either buy out everyone's leases or wait for up to a decade for them to expire. This imposes a huge deadweight cost that wouldn't be there if enough parking had been built in the first place.

Your reflexive concern that parking wont get built is well-founded. Parking is just plain shitty. Let's have less of it.

Only a tiny portion of most metro area populations can live in the zoned housing capacity of central business districts. Only a handful of cities have remotely passable public transit systems. Everyone else needs parking.

And they and their companies can pay for it. There should be more parking garages and less parking lots and on-street parking. It's important to get make all the costs transparent so people can make good decisions. Maybe the office will move from downtown to somewhere closer to their workers -- reducing congestion and commute time.

>And they and their companies can pay for it. There should be more parking garages and less parking lots and on-street parking.

These statements are contradictory! Making business pay for their own results in on-street parking parking lots and minimum parking requirements. When you centrally plan parking you get parking garages.

You are so right. Let's attack both of the challenges you identified, and solve them

> Only a handful of cities have remotely passable public transit systems.

> Only a tiny portion of most metro area populations can live in the zoned housing capacity of central business districts

>Only a handful of cities have remotely passable public transit systems. Everyone else needs parking.

They don't need parking. They need a solution to enable access to the downtown core. The solution you want is parking, because that's the status quo. Improving public transit is also a solution - It's not actually impossible to build.

Building out acceptable public transit over America's vast <1,000 people/square mile suburbia is probably not economical. First you would need drastically higher densities to become socially acceptable and legal. Then you would need decades of building until most of a metro area's population actually lived at high enough densities. Then public transit that's actually competitive with the status quo for mobility could start to pencil out.

Even when the density is there, the social mission of public transit agencies is to be a lifeline for the very poor. Improving service for professional commuters is at the bottom of their priority list. I can't even argue with that: the middle class can drive as an alternative, without bus service the destitute are just stuck.

The solution I want is unlimited construction of skyscrapers and travel mostly by foot and elevator. But if there's one thing our democracy is great at, it's preventing high rises. For the densities we have, our choices are cars or simply having commutes eat further into our already scarce free time. (No, public transit is not free time, as any vaguely useful train is crush-loaded standing room only).

You could have parking spots at train stations that take you downtown. It's not necessary to have a bus stop at every corner in the suburbs.

Indeed, those can work well, but the urbanist community is working hard to remove them (i.e. AB 2923 in California).

It would have to get past zoning/etc. when many cities are fighting to get more people to move into downtown removing buildings and putting up parking may be seen as a problem/eyesore.

I think basic profitability is probably the #1 and #2 answers.

I'm aware of a deal where a consortium bought a plot in a downtown area to build a tower, and demand went down so they went into a holding pattern while making money on the parking.

I didn't see a naive free market analysis in progress, but anyway, I have noticed that people build new parking structures around my urban area on a regular basis. It does take a while, but it happens.