Why Startup Hubs Work

I'm going to guess that this happens in the entertainment industry as well. The similarity being that the person you are rooming with or working with who has a bit part on some show with you might be the next big star. So I would imagine people tend to be nice and helpful to people in any field where there is a big prize and it's not easy to tell (like with sports) who the next star or Spielberg might be. Because in addition to skill (which many have, as has been said with acting for example) there is luck and landing that key opportunity that launches your career. And if you happen to have known or have been friends with that successful person it could only help your career.

"Cities, the dense agglomerations that dot the globe, have been the engines of innovation since Plato and Socrates bickered in an Athenian marketplace."

He also has section in the book assessing the "Rise of Silicon Valley", and makes the point the "innovation clusters in places like Silicon Valley because ideas cross corridors and streets more easily than continent and seas." And he points out an amazing correlation of the geographic proximity of patent citations. "...even in our information age, ideas are often geographically localized."

As the NYT book reviewer of Glaeser's work put it... "Greater density is the goal: more people means more possibility."

Ergo, a greater density of people working in similar modalities means a greater possibility of achieving within those modalities. It also means that those working in other modalities can encounter difficulty getting support, especially when directly competing for resources with the dominant modality. (I.e., startups v financial services industry for programmers.)

What's different about NYC is that there are so many people in great density, that it's still possible to have vibrant secondary modalities that may never supplant the (multiple) dominant ones. It also means that there may be cross fertilization between modalities not possible in other innovation clusters.

What's different about Silicon Valley is that it's a "city" with a single dominant modality - tech (currently Internet) innovation & startups. You can walk entire blocks in NYC without running into someone involved in a tech startup, or go days without talking tech at a social engagement. That is almost unpossible in SV. So SV's advantage over NYC's shear density of people is a density of people operating in the same modality.

Lastly, there are many geographically distributed innovation clusters/startup hubs that each operate in a different modalities. PG is understandably writing about the types that occur in Silicon Valley, because that's what he's most familiar with. And, they produce undeniable, and very public, results!