1. There is an upper bound on price, same as any other asset. The upper bound has yet to be determined, however.

2. Everyone who thought the price wouldn't* continue to exponentially increase was wrong. So far. But this statement totally forgets the fact that shit changes. Anyone who said Yahoo was overvalued before 1999 was proven dead wrong. But after 1999, they were pretty much dead on.

Everything else you said has a 0% chance of happening. Objectively speaking, Bitcoin will probably never become legitimized by any government. We're just testing how big a bubble gets.