Even though this essay has tried to capture how technology startup hubs work and SF in specifc , but this is how every every other hub works . Let it be finance(Wall street),cinema(Hollywood),art(Florence).All these have similar couterparts accross the world. My thesis is, it has more to do with the people who first come and establish a successful enterprise and develop a culture that attract more people .Something like how people were attracted to the gold rush(this had more to do with luck than talent) And also the presence of supporting infrastructures.Presence of Stanford, Berkeley,etc. Stanford almost has a symbiotic relationship with the valley.

And it should not be of any surprise in any kind of hub ,that even if collaboration does not happen abetment will happen. Purely because of the large presence of like minded people.

One good thought experiment would be to think of former hubs that have lost their culture. Thinking of that,I realize only hubs formed around matter (cities that sprang up around mines and oil wells) have been lost while those that rose on ideas will stay for a long time thriving with life,hope and innovation.

PS: I am a little surprised that PG notes that he meets so many techie people in his day to day life.