Do you think that he wouldn't have done what he has done if there was a wealth tax in the US? Do you think he can put money to better use for all of society than a good government? (And we can discuss if the US government is a good government in that sense, but that's beside the point I'm making).

I'm pretty sure the answer to these questions is No (he would have still done it) and No (a good government can put money to better use for all of society).

Or do you think the single mom with 3 kids working 2 jobs and still can't pay rent and health care cares about electric cars and rockets?

Edit: I still think what he's doing is important and impressive, and it's ok that he is one of the richest people on Earth. However, that doesn't mean the US needs to have a better tax system for the rich and better social pillars.