The gold rush is deeply embedded in the Bay Area psyche. This is not a place to grow old; this is a place to seize the day and make the most of your youth. So much about the region is both wonderful and terribly fragile over time.
I think that's true for a demographic - the San Francisco 24-35 demographic (especially those in the tech sphere of influence), but I don't think it's generally true across the bay area. People who tend to think like this tend to be transplants that do not know very many people over 40, they don't know anybody from, say, Redwood City, Hayward, or Albany or even the Sunset district. I say this as a transplant under the age of 40, but the majority of my coworkers are much older despite most of them also being transplants.
My in-laws have been here 35 years. They are old-school now: they own a home, they oppose further development or upzoning, they worked as a mechanical engineer in defense and a biologist in biotech. Nevertheless, when they were in their late 20s, they were recent immigrants from another country.
Their neighbor is close to 90. She's even more removed from today's gold rush: she was a secretary & later HR manager at one of the early electronics companies. IIRC, she came here as a child in the 30s, one of the dust bowl & depression migrants.
I'm reminded of a line from last week's Game of Thrones episode:
The history of the Bay Area has been one of successive migrations, each of which comes seeking wealth & fortune and each of which is ultimately displaced by the next as it taps out the economic boom that started it. It started with the gold rush (1848-1855). Just as that was winding down, the railroads (1863-1890) took off, leading to widespread immigration first of white Americans fleeing the Civil War and devastation there and then of Chinese and other Asians. The 1890s and 1900s were a rough couple decades for San Francisco, between endemic corruption, a bubonic plague outbreak, and the 1906 earthquake and fire, but from 1910-1930 you had a large migration of poor white farmers ("Okies") fleeing economic consolidation and environmental destruction in the plains. From 1930-1945 you had the huge U.S. military buildup and a large migration of largely black workers; SF was both an important port and shipbuilding center. After the war Fred Terman made sure that Stanford and associated companies got a large share of the Cold War DARPA dollars; this funded HP, Shockley, Fairchild, Varian, Lockheed, Hendy Ironworks (now Northrop Grumman), Moffett Field, and most of the first-gen Silicon Valley companies. This branched off into consumer semiconductor & electronics manufacturing in the 60s & 70s, with Intel, National Semiconductor, TI, Seagate, Apple, etc. While this was going on, you had the countercultural revolution up in SF. Then you had the PC revolution in the 80s, then the dot-com boom in the 90s, and then the Internet, mobile, and sharing-economy booms of the 2000s & 2010s. Now you have a significant blockchain & AI presence up in SF. All of these are fueled by a mass migration of young people from more disadvantaged areas of U.S. like the Midwest & South, as well as a large influx of Chinese & Indian immigrants.
It's always been a place where people come from far away to capitalize on the zeitgeist, and if you're not capitalizing on the zeitgeist (or supplying shovels to those who are), you're marginalized. When the zeitgeist turns, everybody who made their money in the previous iteration looks to invest in the next one. If you call the next one wrong, you fade away into obscurity.