I'm with you. I'm not convinced it will happen because we can't get our shit together on Earth. We're screwing this planet up, and I'm not convinced we'll ever even have the opportunity to screw up another one before some sort of massive extinction-level event of our species.

That being said, read The Night's Dawn trilogy. The undercurrent of those books is that we settled many planets specifically due to social/racial differences that we couldn't settle on Earth, but that aren't such a problem in space. It's an interesting take on the whole mess.