In this respect he strongly reminds me of Mencius Moldbug. However, also like Mencius, he seems to have a very political/social focus which fuels my suspicion that many of his top down "grand theories of how reality works" are false.

Oh yes, this is the aptest comparison on the page (a comparison to Robin Hanson would not be amiss either), except I get the feeling that Moldbug is more of a single big idea thinker than Rao (if you used Tetlock's dichotomy, Moldbug is a very happy curled-up hedgehog, and Rao would be the fox, possibly a fox on Adderall).

Both are provocative thinkers who probably are only occasionally truly right. But that's better than most writers, who are never right or provocative.

His book took me by surprise. I expected it to have the same style and sort of content as his blog (like every other blogger who writes a book) but it was completely different. It consists of half a dozen (unrelated) chapters that end with an exercise. I'm not sure if Tempo is any good (I suspect his solutions overfit the data) but it's short (130 pages or so) so there's no reason not to pick it up if you like the way Venkat thinks.

I'm taking the liberty of adjusting your estimate of wanting to buy the book upwards to 30%.