> Its also local demand, diversity, merit, culture and acceptance and many other things. Plus existing inertia matters too. It takes tons of effort to get the ball rolling.

I think the last point is the most important one. It also took a lot of government/military/intelligence funding to get the ball rolling, and a time where the government/military/intelligence wanted to fund specifically that, something you cannot simply copy. The weather, local culture etc were available before, but SV didn't become a major player before all the stars aligned just right.