If you look at a list of US cities sorted by population, the number of successful startups per capita varies by orders of magnitude. Somehow it’s as if most places were sprayed with startupicide.
I wondered about this for years. I could see the average town was like a roach motel for startup ambitions: smart, ambitious people went in, but no startups came out. But I was never able to figure out exactly what happened inside the motel – exactly what was killing all the potential startups. 
A couple weeks ago I finally figured it out. I was framing the question wrong. The problem is not that most towns kill startups. It’s that death is the default for startups, and most towns don’t save them. Instead of thinking of most places as being sprayed with startupicide, it’s more accurate to think of startups as all being poisoned, and a few places being sprayed with the antidote.
Startups in other places are just doing what startups naturally do: fail. The real question is, what’s saving startups in places like Silicon Valley? 
I think there are two components to the antidote: being in a place where startups are the cool thing to do, and chance meetings with people who can help you. And what drives them both is the number of startup people around you.
The first component is particularly helpful in the first stage of a startup’s life, when you go from merely having an interest in starting a company to actually doing it. It’s quite a leap to start a startup. It’s an unusual thing to do. But in Silicon Valley it seems normal. 
In most places, if you start a startup, people treat you as if you’re unemployed. People in the Valley aren’t automatically impressed with you just because you’re starting a company, but they pay attention. Anyone who’s been here any amount of time knows not to default to skepticism, no matter
how inexperienced you seem or how unpromising your idea sounds at first, because they’ve all seen inexperienced founders with unpromising sounding ideas who a few years later were billionaires.
Having people around you care about what you’re doing is an extraordinarily powerful force. Even the most willful people are susceptible to it. About a year after we started Y Combinator I said something to a partner at a well known VC firm that gave him the (mistaken) impression I was considering starting another startup. He responded so eagerly that for about half a second I found myself considering doing it.
In most other cities, the prospect of starting a startup just doesn’t seem real. In the Valley it’s not only real but fashionable. That no doubt causes a lot of people to start startups who shouldn’t. But I think that’s ok. Few people are suited to running a startup, and it’s very hard to predict beforehand which are (as I know all too well from being in the business of trying to predict beforehand), so lots of people starting startups who shouldn’t is probably the optimal state of affairs. As long as you’re at a point in your life when you can bear the risk of failure, the best way to find out if you’re suited to running a startup is to try it.
The second component of the antidote is chance meetings with people who can help you. This force works in both phases: both in the transition from the desire to start a startup to starting one, and the transition from starting a company to succeeding.