Quite a bit of historical momentum.

>UK has Oxford, Imperial, Cambridge, and money

One reason UK still has these things after all those centuries, has been growing hesitation to take chances with any of it. These assets are super-valuable beyond measure, only one of the above is completely replaceable, others are something "money" just can't buy. And hesitation is proven to work, so they're only doing what works, preserving the assets at the cost of missing out on the occasional bonanza. The UK leadership in these areas is still world-class and that hasn't been lost regardless of whether it was before, during, or after the USA even existed and/or had its own maximum impact.

Meanwhile not that many people had any interest in the Spanish Mission for St. Francis until gold was discovered not that far away, and this was the closest thing to civilization there was. Got crowded but not exactly too "civilized" for quite some time either, females drastically under-represented. The original purpose for most people to flock to SF was speculation before there were any crowds, and that's what built the size of the citizenship more than anything else when it did start booming. And speculation overwhelmed almost everything else for the longest time.

So you've got a completely different foundation which was built upon in different places like this.

I would say the original attitude can have longer-lasting momentum than you think, even after significant dilution, especially if there was a fairly strong consensus to begin with.

Now back before SV took off I wasn't following the money as closely as I could have, but I had always been well aware that Wall Street would be an easier place to find investors for novel businesses than overseas. When UF came out with Gatorade that lit a fire under MIT that got brighter than anything else real quick, and that's when I recognized Cambridge MA USA as more likely than Wall Street for a technical entrepreneur who wanted access to capital, to thereby start becoming a capitalist themself.

West Coast gold was long gone by then but I would think when "SV" got started in SF there was still plenty of "residual" wealth that had grown rather than dwindled. A lot of growth probably realized from other things like Wall Street, farming or real estate. Oil showed up along the way too. I got the idea what really set it off was once Hollywood windfalls started skyrocketing beyond expectations, this happened when digital was just becoming the greatest growth prospect for investors. Seemed like that's where lots of the new money was coming from and it came in pretty quick where there were not nearly as many technically qualified leaders to invest in as there was money to burn.

So SF became the most likely place for a technical innovator to become a capitalist, even better than the East Coast where there were still way more sources of capital.

Ask HN: Why SF? Why not India? UK? Or anywhere else?