Not every person is smart in every way. Some people are very good at reading technology, some are very good at reading the motivation of other people. It could be that Carmack mistook Zuckerberg's intentions with Oculous and believed him on the handshake promise (I'm giving a lot of grace to Carmack... it's hard to see people you respected fall by the wayside).
I highly doubt that the metaverse thing (VR ad mass market or whatever) can work out economically. Therefore I read the Meta rebrand as an enormous personal hybris project, "I've succeeded before and I'll succeed again (and this time even if I fail I'll still have more money than I can ever spend)". The intentions are all late 20th sci-fi dreams, fully in line with what an idealized Carmack might like.
From that tech dream perspective, which I assume they both share, the Facebook way of making money while chasing those dreams is just circumstantial details. For both of them. I'd expect those two to get along excellently. One of them is now basically renaming his life's work out of admiration for what the other can do, and the other is probably not infinitely immune to flattery.
