Didn't have a shuttle, or the possibility of commercial companies contracting the work. Spaceship one didn't cost as much in real terms as Mercury - not by a long shot.
As for the problem with g - true they might be there - but the 'problem' might just be with free fall, not reduced gravity. Of course, we'll never know if we stay here.
And waiting 'till Red Giant phase? The Neanderthals didn't last that long, and they lasted longer than we have so far. I really don't think we have that long.
And - a few thousand years? The length of time the West has been 'civilised'? 10 times the length of time we've had an industrial civilisation? Again, I dunno. I don't think we have the time to dawdle.