Attempt at the briefest content-full Less Wrong post:
Once AI is developed, it could "easily" colonise the universe. So the Great Filter (preventing the emergence of star-spanning civilizations) must strike before AI could be developed. If AI is easy, we could conceivably have built it already, or we could be on the cusp of building it. So the Great Filter must predate us, unless AI is hard.
I dispute this assumption. I think it is vanishingly unlikely for anything self-replicating (biological, technological, or otherwise) to survive trips from one island-of-clement-conditions (~ 'star system') to another.
Nick Beckstead wrote up an investigation into this question, with the conclusion that current consensus points to it being possible.