The solution to the paradox is that a chimpanzee could make an almost discontinuous jump to human level intelligence because it wasn't developing across the board. It was filling in a missing capability - symbolic intelligence - in an otherwise already very highly developed system. In other words, its starting point was staggeringly lopsided. [...]

Can such a thing happen again? In particular, is it possible for AI to go foom the way humanity did?

If such lopsidedness were to repeat itself... well even then, the answer is probably no.

Chimpanzee brains were screwed - because they lacked symbolic processing - OK.

...but human brains are still screwed - since they have a crazy spaghetti-like architecture, have terrible serial performance, have unmaintainable source code, crappy memory facilities, and they age and die without the possibility of a backup being made.

So, human brains will go into the dustbin of history as well - and be replaced by superior successors, moving at the more rapid pace of technological evolution. Surely this one is not difficult to see coming.