Stick to the knitting
Physicists should do physics. Speculating on the sociology of space civilisations is not their forte. I am put in mind of Penrose's stab at explaining why artificial consciousness could not exist (a computer cannot answer the question "how do you feel"). Hawking also made the bold statement that if we could find the grand unified theory we would "truly know the mind of god". Try defending that argument in an undergraduate level philosophy course. If this theory was the only justification for the spending money on NASA, I'd pull the plug.