To be clear, I don't think Musk is trying to seize power. I think probably his self interest in this regard is what he has said for a long time, he wants to put a colony on mars. I think he feels like he will never be able to do that in a US where the government just harasses it's political enemies every time the executive branch changes hands and lines the pockets of it's allies. So I do think his personal interest aligns with the public in this regard, and that's why he's doing this stuff.

Of course, ambition to essentially own a mars colony means dictatorship over a planet, a mars colony would be an environment where air and water aren't free, all the people there would be de facto property of the corporation that owns that colony. That's a much bigger ambition IMO.