> My guess - he'd be in a conflicted position if he ever wanted to start / do his own social network.

That would likely take his time away from other things he cares more about, such as Tesla and SpaceX. Whereas buying up Twitter stock – even buying 100% and taking it over completely – doesn't take up much of his time at all. Even a board seat would have only been a modest time commitment, far less than starting a new social media company from scratch would be.

> And these changes are WAY outside of the comfort zone of FTC etc.

Why would those changes be outside the FTC's "comfort zone"?

FTC's chief concerns are (1) consumer protection, (2) antitrust/competition. I don't see how the changes you mention would impact either.