I'd say many if not most of the startups YC funds have the potential to go public, if the founders were sufficiently driven. (In saying that I'm relying on the fact that practically no companies that go public look like they will at the start. Apple started out as a company that was going to sell plans for computers.)
Wow that's something I haven't entirely considered, despite knowing it to be true. Somewhat adds to my argument, however, without the chilling effects of regulation we may have seen a more interesting and diverse market -- but now I am in purely speculative realm.