I wonder if SF could experience some tech detroitification in about 10-20 years, or possibly sooner.

As a tech worker here, I and others engineers I know are becoming disenfranchised with the housing prices around here to the point that I'm casually exploring where I might want to move next in 4 years or so if this situation doesn't reverse itself.

With the number of engineers all feeling the same, it's possible to find enough people to willing to be a co-founder and move to a much cheaper part of the world during the formative months/years when your company is pre-profit. Take Silicon Valley investing connections, a mobile workforce, rising housing prices and you basically have a confluence of forces that will accelerate a diaspora of engineers to more places in the world without necessarily giving up on the tech community that makes SF so desirable. Once decent sizeable tech communities show up in more places, the greater the likelihood that engineers in the Bay Area look around and tell themselves "This just isn't worth it. I'm paying a premium to be around colleagues, but now my colleagues are everywhere and it's just not worth it anymore."

At the end of the day every engineer without rent control is going to face a financial decision once a year when rents are raised that could make moving elsewhere more attractive. What's the point of improving at your job and earning raises when most of your raise ends up going into your landlord's pocket. Do that 2-3 times and you are either going to look into someway of getting into rent control unit or you're going to start considering other options elsewhere.

All you really need to stay in the area for is to create a solid enough professional network that you'll gain access to the smart capital in the region. Once you have that, you can go anywhere since investors will know you, what you're capable of and that investing in you and your business is a good idea. If this happens often enough, you're going to start to see more VCs comfortable with this approach that they'll be able to tell offer job candidates coming through the VC hiring offices positions in portfolio companies located in places that might be more desirable to a tech worker than SF.

I stay in SF because some of the most interesting tech jobs are here. Once that is no longer a valid assumption and my professional network is sufficiently geographically distributed, I no longer have anything tying me solely to San Francisco.

I can't count the number of conversations I've had with other engineers about thinking about moving to Berlin or Portland or even trying to set up shop in some cheap remote paradise where we would have the financial liberty to invite friends to come out and hang out in a guest room for weeks to months at a time so long as they pay the airfare and living arrangements. Top places on my list when I entertain ideas like this are small beach towns along the Northeast of Brazil. I'm often amazed at how many of my engineer friends are onboard with this ideas, more than willing to exchange San Francisco so long as they know they will have engineering peers and interesting engineering problems to solve in some other locale.

Even the cultural attractions that made San Francisco awesome have been co-opted by the hipster culture and gone mainstream enough that SF no longer has the strong lead on novel cultural innovations that it once had.

"It's an odd thing, but anyone who disappears is said to be
seen in San Francisco. It must be a delightful city and
possess all the attractions of the next world"

-- Oscar Wilde

All the attractions of the next world are starting to crop up everywhere more and more and here in SF less and less. Eventually the barrier to going elsewhere and still working on fun engineering problems will be easily surmountable.