10-12 years ago, there was no tech in SF. Zero. It was mainly financial companies or workers for Levi's, Gap, etc. All the best tech companies were in South Bay. It was Twitter, Zynga, Yelp and quickly followed by Uber, Airbnb, and all the other cool startups that brought tech into SF and probably the cause of that shift. SF started giving tax breaks to tech companies in the late aughts, and then it started the huge migration of tech startups from South Bay to SF.
Before that, it was rare for tech workers to live in SF. Most would live in South Bay and come up to SF to party on weekends.
Also, salaries went crazy in the last 8-10 years. Once all these rich tech workers came to the city that thought they knew best because they were rich and young, that's probably what caused the shift.
Having been here since the dot com boom in the 1990s I have to disagree. Large firms headquartering in SF is a relatively new thing, but there were plenty of small firms attracted by VC money but which didn't come out of the Stanford orbit that has shaped SV.
I've been here since the 90s as well, and I can't think of a single major company that came out of SF until recently. Not enough to cause a huge shift in where people worked.
I'm pretty sure this is incorrect. SV has been host to tech companies (for the varying definitions of "tech") throughout the decades, from early processor and PC companies, video game companies, early internet companies, and Web 2.0 companies.
Do you mean SF or SV? Silicon Valley traditionally ended at Palo Alto in the North. It was only recently, ie. last 10 years, where tech companies moved out from Palo Alto. Only a few scant companies were outside of prime Silicon Valley until then.
Before that, it was rare for tech workers to live in SF. Most would live in South Bay and come up to SF to party on weekends.
Also, salaries went crazy in the last 8-10 years. Once all these rich tech workers came to the city that thought they knew best because they were rich and young, that's probably what caused the shift.