"In the long run, we're all dead." -Keynes
It took generations for a second Motor City to emerge outside of Detroit. New York is still the unchallenged capital of the finance and fashion worlds. There's no "Second Hollywood" in the United States. There's a Reno and an Atlantic City, but neither holds a candle to Las Vegas.
What makes you so certain tech will have an exodus from San Francisco between now and the year of your retirement?
Look into what's been going on in Georgia for the past few years. Not a replacement for Hollywood yet, but it's a good example of how quickly alternatives can take off due almost entirely to geographic differences in the cost of doing business.
The costs of doing business in Atlanta are significantly less than other regions.
And while they likely have convinced a few companies (they like to showcase a half dozen or so), it's not like it even was a measurable blip on the growth of game companies in Silicon Valley.
Most people don't realize it, but many recent high-budget movies were filmed in Georgia, e.g. Fast Five, Vacation, Ant-Man, all three Hunger Games movies, one of the recent X-Men movies, Flight, etc. After 2008, there was an abundance of empty warehouse space here available at deep discounts, not far from the highest volume airport in the world.
As the economy rebounded, momentum in that industry seems to have remained even though there aren't many empty/cheap warehouses here anymore. A few developers are even working on purpose-built movie studios around town now.
It has been interesting to watch, and certainly could parallel what could happen in the bay area if an exodus to somewhere like Austin began in earnest.
Tech Austinite here -- given the rate prices of food, housing, etc. are spiking here, I'm presently more inclined to see ATX as catching up to SF prices and acting as an SXSF than remaining a low-cost alternative.
Don't generally disagree with your thesis, but at least for tech I don't think the game is zero sum, and the market is expanding fast enough to support multiple tech hubs.
It's right here in Atlanta. It's been a decade and a half in the making, and the pace and scale of it increases with every passing year.
Pinewood: http://m.pinewoodgroup.com/our-studios/usa/pinewood-atlanta-...
Third Rail: http://clatl.com/freshloaf/archives/2015/04/07/film-and-tv-s...
Tyler Perry's new facility: http://m.clatl.com/freshloaf/archives/2015/06/29/tyler-perry...
This is just three of about ten studio facilities being built in the area.
I believe three of the Marvel films have been filmed in Atlanta. These have been recent enough not to be in that list.
I know this is anecdotal, but if you were living in Atlanta you'd get a sense of how much growth is occurring in our film industry.
That's the thing... Technical people are still cheap. Really cheap, compared to the jobs where your asset is "knowing people" - our salaries haven't been increasing with the cost of living around here, unlike the real-estate agent example below.
Look at what you pay a body shop for developer time. A lot of that goes to the body shop; the people who's main asset is the "relationship" with management.
Heck, at 3%, become a real-estate agent. sell three or four houses around here a year, and you'll make more than your average developer or sysadmin.
Yeah, wake me up when we make more than recruiters. Until then, I'm going to ignore all this noise about technical people being expensive, because it's obvious bullshit.
All that said, while I don't think the cost of us is a problem for companies, the high cost of living is a problem for us. As a technical person, the bay area only really makes sense if you are the best of the best (or have those "relationship contacts" and can get real money) - for the rest of us, it mostly only makes sense if you have a deep emotional connection to the place and/or have a rent-controlled space. (In the south bay, if you own, live with family, or have a landlord who doesn't jack up rents with market... there's no actual rent control in the south bay, though I know a few people paying vastly below-market rents because they've been renting from the same person for a decade or more, and that person is being cool. There's serious rent control in San Francisco proper.)
This... is probably why companies are opening up branch offices; there are many good people who just won't move here because the cost, but that's because we aren't expensive enough, not because we're too expensive.
So why would we move there, if we can get paid pretty much the same with a much cheaper cost of living? The extra connections are not worth going from 1K a month mortgages to 4-5K.
But perhaps more interesting is the salary question, because there is so much resistance to raising salaries it pulls companies out of the Bay Area. (which has been true since I started here in the 80's) I am not sure what the opposite of a bubble is (not enough increases relative to the market) but as far as I can tell the whole country is in one of those. At some point someone is going to just say "Screw it, staff for effectiveness even it it doubles our HR cost." and if that entity successfully captures the top performers it will seriously outperform all of its competitors in the market and light off a wage war which was what happened in the late 70's and 90's in the Bay Area.
Its not a free market, there are regulations.