At the beginning, there is always a 'center', but that does not negate the influence of the other districts.
I suspect that PG has gotten caught up in a bit of the valley hype.
There are many more counterexamples. Microsoft (does it not count because it was pre-internet?) was a start-up outside the valley at one point. MySpace didn't start out in the valley. So why skype? because a valley company overpaid significantly for them? (I love skype though, i just don't think they are the best counterexample).
Detroit thought it had all the 'talent' and 'knowledge' in building cars, and then got it handed to them on both sides, cheaper and better from Asia, more expensive luxurious and better from Europe.
No question the valley has investors, and very talented ones at that. As costs for internet start-ups decreases, amazing open-source technologies like hadoop continue to spread, and talent realizes they can excel anywhere, why would the valley continue to as the center?
What will be the draw to keep people in the valley? Angel financing can now accomplish what only VC could a few years ago, and that continues to change. Ideas are not limited to the valley, technology is not limited, for many start-ups their are no physical goods, and when there are, those are created overseas.
So, though Silicon Valley may be the center today, what will make it the center tomorrow?
This comment seems to disregard the point of PG's essay. He's describing a network effect. Just as it's hard to create a startup community (not a single startup, as in your examples) you need the types of people who build startups present or on their way. The valley is full of people who are interested in startups and work with them to some capacity. It would be difficult to attract someone interested in startups to move to New Haven when there is already so much attraction to the valley. It's true, you could start a startup anywhere. It's probably going to happen in the valley.
