Personally, I assumed he had multiple overlapping motivations. Prove that he knew tech products better than SV insiders, own a major media platform to push his viewpoint, save a media platform from "woke" people and let people like Trump back on, silence his critics, make money, pretend he really intended to purchase something he didn't actually want to. I'm not sure that even he knows why he does what he does, because so much of it is impulsive and can't be attributed to a coherent plan with specific goals.

The only thing that will definitely hold true is that there is an audience of tens of millions of Americans who feel mocked by "the Elites." They will shower adoration on anyone with Elite creds - be it academic, media, or business - who tells them there really is a conspiracy to oppress them and that they're the straight shooter who will go to battle for them. That is a very seductive amount of positive feedback when the other things you're doing aren't home runs.