VCs prefer investing in companies in NYC and the Valley. So Paypal would have probably had to be built in one of those two markets. Once he had a successful company, I suspect he could have gone elsewhere and still received investment and convinced enough talented people to come join his projects. So I think for Elon in particular the answer is yes, but there might have only been a single other place he could have started in the USA, and we're specifically talking about Elon.