There are many significant physical roadblocks at the moment, and putting aside how cool I think that a galactic civilization would be, I'm not sure we can remove enough of them to achieve that goal.

FTL travel is impossible, and even the fastest ship would take centuries to get anywhere outside our solar system. That alone will restrict us to our little corner for the next millennia at least. Of course I reserve the right to change my mind if there's some groundbreaking discovery, but I find it unlikely. Add to that the possibility that we wipe ourselves out of existence (or the planet does), and I don't see ourselves getting to our 1 million year birthday.