My mind about this was recently changed by David Kipping's "red sky paradox": www.youtube.com/watch?v=IrUi... Currently, I am not sure what to believe. The answer could either be a smaller habitability window than we think, or it could be grabby aliens.

One place where I disagree with Hanson is his focus on 'loud grabby' civilizations, perhaps because it allows him to constrain his model. But I would argue on strategic grounds that if a civilization can be BOTH stealthy and grabby, it would most likely choose to do so.

What makes this much sharper - both Fermi's paradox and Hanson's GA hypothesis - is that we are technically reachable from hundreds of millions if not billions of other galaxies (www.sciencedirect.com/science/arti...).