There's people who will think any issue is stupid, but by no mean did the vast majority of people think those ideas were stupid. I particularly don't recall anyone saying reusable rockets were a bad idea.
And X.Com didn't become Paypal. Paypal became Paypal. Paypal was already developed before the merger and it was not Musk's idea.
As absolutely insane as his goals are, betting against him overall tends to be a losing bet. I'd be careful about what you think SpaceX "isn't" going to do. If it is technologically possible, they will do it. Period.