The actual paper is an interesting read. They present an actual computational proof, stating that even if you have essentially infinite memory, a computer that's a billion times faster than what we have now, perfect training data that you can sample without bias and you're only aiming for an AGI that performs slightly better than chance, it's still completely infeasible to do within the next few millenia. Ergo, it's definitely not "right around the corner". We're lightyears off still.
They prove this by proving that if you could train an AI in a tractable amount of time, you would have proven P=NP. And thus, training an AI is NP-hard. Given the minimum data that needs to be learned to be better than chance, this results in a ridiculously long training time well beyond the realm of what's even remotely feasible. And that's provided you don't even have to deal with all the constraints that exist in the real world.
We perhaps need some breakthrough in quantum computing in order to get closer. That is not to say that AI won't improve or anything, it'll get a bit better. But there is a computationally proven ceiling here, and breaking through that is exceptionally hard.
It also raises (imo) the question of whether or not we can truly consider humans to have general intelligence or not. Perhaps we're not as smart as we think we are either.
Bezos might expect Trump to win and wants to avoid retaliatory actions from Trump if he does.
He knows Harris won't hate him for the lack of an endorsement, or at least won't vindictively come after him. Trump is... less mature.