Probably not spite, but Tesla and SpaceX are exposed to government subsidies and contracts, respectively. If the next elections unlock another trillion in market value for his firms, this bet might look a lot better.

Small nit pick: Musk didn't put up $44 billion. His commitment is about half that, with the rest coming from other investors (e.g., a16z, Sequoia, individuals) and debt issued by Twitter, Inc.