> Corollary: our brains are basically the dumbest possible solution evolution could find that can host general intelligence.

I agree. But there's a very strong incentive to not to; you can't simply erase hundreds of millennia of religion and culture (that sets humans in a singular place in the cosmic order) in the short few years after discovering something that approaches (maybe only a tiny bit) general intelligence. Hell, even the century from Darwin to now has barely made a dent :-( . Buy yeah, our intelligence is a question of scale and training, not some unreachable miracle.