This surprised me so I looked some stuff up. From this article, it appears Musk has economic reasons for opening up some patents for his companies. Also, Tesla has a boatload of them and SpaceX has hundreds, though they don't seem very valuable:
If patents are “for the weak” as Elon Musk claims, why is he patenting his inventions? Here’s an in-depth look at Musk’s IP strategy.
www.patsnap.com
Psychologically, I think Musk is so wealthy now, I doubt he would be trying to rig the govt system to make him much more so (although I'm sure he won't be suggesting anything that would materially affect his own business interests).
I'd guess at this point he wants to be recognized in history as someone great (vanity) and advance his own values. And if he can put his mark on the most powerful nation on Earth, so much the better in that regard.
He's smart, but I'm not sure engineering smart translates to govt/political philosophy smart. It can, of course, but I don't think it's necessarily the case.