Maybe there's always a bottleneck to the wealth you receive, but there's no such bottleneck to the wealth you create. You're not limited in in your creation just because some other startup is doing well.

That's also true of working at a larger company, except that larger companies usually have their wealth (product, service, whatever it may be) created and are trying to get more money out of it. Working at one is generally going to involve less raw wealth generation than working at a startup, which I think is part of what the author is trying to say.