In my experience, it is largely attributable to local culture. The intersection of high-quality engineering talent and ambition bordering on megalomania is quite rare, but you need it to build a strong tech-driven company. In the vast majority of places in the world, and even in much of the US, this is neither socially prevalent nor culturally accepted. You have this in the Bay Area and to a lesser extent Seattle, but not too many other places in my experience.
There are a number of cities around the world that have high-quality engineering talent in sufficient quantity, that part is easy to replicate. The complaint I consistently hear from startup founders across Europe (where I've worked) and in some parts of the US is that there is a broad and deep-seated lack of ambition or appetite to do very difficult engineering. The reasons for this are multi-faceted and complicated, so it isn't something that can be reduced to a soundbite or easily changed. The intensity of effort applied to technical problem solving that we take for granted on the west coast is very much not the default case most other places, and this is compounded by the relative lack of experience building high-performing engineering organizations.