I think the single key element is "lots of smart people want to be there", with a secondary element of "lots of smart people are able to be there". Everything

I think the single key element is "lots of smart people want to be there", with a secondary element of "lots of smart people are able to be there". Everything else is secondary, although capital is a serious accelerant. I wonder what other places have this trait. University cities where smart people leave after university don't meet it. Japan probably has the "lots of smart people want to be there" (the huge population of hacker type people worldwide who love Japanese culture), but either can't be there (due to a weird employment/immigration market), or the country itself is too difficult for a nexus of startupness to form. Singapore and Dubai are awesome, but most of the expats I know in both places have a "want to make money for a few years then go home" view of the places. SF, NYC, LA, Boulder seem like the most aspirational cities in the US. SLC for the Mormons. Maybe Portland?