Over-dependency on a single industry, unwillingness to diversify, and an arrogant assumption that the same work could never be done elsewhere. Add in highways, commuting, and an infrastructure maintenance death spiral as domestic car production lost its major advantages. Rising crime added to the death spiral, as people who could moved out and the general deprivation of Detroit grew.

Many of the suburbs developed their own economies, which further encouraged people to move there instead of Detroit proper.

Lots of racism played its part in various ways. Lots of room to debate the precise degree, though the debate is probably not helpful at this point.

These days the high taxes (property and income) and auto insurance rates are big problems.

Only a few of these really apply to SF. Though the arrogance of assuming the good times will roll on forever seems accurate.

"Over-dependency on a single industry, unwillingness to diversify, and an arrogant assumption that the same work could never be done elsewhere."

Like San Francisco?

Only to the extent that San Francisco is over-dependent on tourism. "Tech" is both not really a single industry in the way that auto mfg is and far less dominant than one might guess.

Though if you can convince me that Salesforce and Autodesk are meaningfully in the same industry as Spring and LendingClub, I'm all ears.

There seems to be an awful lot of overlap between the positions they are looking for in San Francisco:

Salesforce: https://salesforce.wd1.myworkdayjobs.com/External_Career_Sit...

Autodesk: https://autodesk.wd1.myworkdayjobs.com/Ext/2/refreshFacet/31...

VMWare (which owns Spring): https://careers.vmware.com/main/jobs?page=1&country=USA&stat...

LendingClub: https://lendingclub.wd1.myworkdayjobs.com/External/0/refresh...

Sr. Release Engineer/Build Engineer, Director of Data Initiatives, Sr Staff Engineer Cloud/Saas Security, Sr Product Designer...

If everyone is doing web/mobile development and they suddenly realize that web/mobile development doesn't need to be done in a 2-square-mile area...

You're absolutely right! The companies I mentioned do hire many people with similar skills.

Do you think it's possible that this might not be quite the same as being in the same market and thus being a direct commercial competitor for a company's offerings? Otherwise every company is in the Human Resources and Accounting industries. Perhaps the companies in question are not in commercial competition with one another, and only competing for a certain set of skilled technicians? Do you think the point imtringued made about downstream suppliers might be relevant?

Again, you're completely right. There genuinely is a lot of overlap in titles and skills sought! It just might perhaps be possible that this is not quite the same as all companies concerned being in the same industry. Or perhaps I am wildly wrong! Can you help me with where I might have erred?

The question of how one chooses to define an industry quite aside, the degree to which San Francisco's employment depends on "tech" is easy to overstate. Based on news and this website, you would think it was a third to a half of SF jobs. While an easy and completely understandable conclusion to draw, this would be a dramatic overstatement.

Detroit's problem was not that the companies there were direct competitors, it was that all of them were producing automobiles. When American automobile production moved elsewhere and took a large number of well-paying jobs with it, the bottom fell out of the city's economy.

What do you expect to happen to San Francisco if it loses its "tech mecca" status? Will the financial sector or the tourism sector supply enough high-paying jobs to make up the difference, or will the money drying up cascade down through the service industries?

I can see I have been unclear.

Detroit's problem was that automotive production was and is a single sector. This is not true of "tech", as shown by a random sampling of companies being in wildly different economic sectors.

I hope this is better! Thank you for the chance to improve my communications skills. Have a nice day.

> I hope this is better! Thank you for the chance to improve my communications skills. Have a nice day.

Unrelated, but I've always found it interesting how people try to avoid appearing like they're actually invested in the conversation they're having and the effect the results have on them.

"I'm not here to exchange ideas and make my understanding of the world better, no, I'm just here to improve my communication skills and I want you to know that!"

I understand the need for self-preservation, but going to this length of lying to yourself and observers to defend your ego is amusing in my opinion.

I use it to place the blame of someone refusing or failing to understand on myself. The goal is not to signal a lack of investment, but to give someone a way to admit to being wrong without actually having to admit to anything. It sometimes helps remove a person's ego as an obstacle.

It's the difference between "I failed to be understandable" and "You failed to understand". With the former, they can come back and say that since I've clarified so helpfully, they agree with me without impugning their previous position. The latter allows no such latitude.

> but to give someone a way to admit to being wrong without actually having to admit to anything

It also shows that you have no humility and can't accept that you might be wrong. That's what I'm trying to say.

> It's the difference between "I failed to be understandable" and "You failed to understand".

You can't even imagine a situation where the other party in the discussion understands your perspective but simply disagrees?

> It sometimes helps remove a person's ego as an obstacle.

Start with yourself.

As an aside, I understand your argument. I simply disagree.

Tech is not a single sector, but it is a single method of doing things. In the same sense that factories exist in more than a single sector, but it largely disappeared at the same time with offshoring.

If, hypothetically, all the issues with having development teams cheap parts of the world went away, that would impact almost all of tech. It hasn't happened yet, but I wouldn't rule out the possibility.

Honestly, that would be amazing. It would enable a golden age of technological development. I think it's just a bit more far-fetched a near-term future than a single economic sector leaving a particular area, and not really directly comparable to Detroit's story.

Car manufacturing needs lots of downstream suppliers that usually have expertise in nothing but automotive parts. The end result is cars and nothing else.

You can build tech for car manufacturers, you can build tech for taxi companies, you can build tech for restaurants, you can build tech for any industry.

San Francisco is still a major financial hub by the way.

According to this talk [0] the reason is that the newly established car industry encouraged a massively unsustainable development pattern that eventually led to the bankruptcy of the city and since its the first city to be built with this pattern it was also the first to fail. Lots of other cities are suffering the same fate. New low density development at the edge of town at the expense of the self sustaining downtown core and then at some point the maintenance costs exceed the tax income and you get a city wide decline.

[0] https://youtu.be/Em7nqDqQ8oM