Buffett has pledged to leave 99% of his fortune to philanthropic causes when he dies, still lives in the same house in Omaha he bought in the 1950s, and doesn't own a megayacht or private jet. In what way is he a "leech"?
A lot of what he owns (through Berkshire Hathaway) is basic infrastructure without which the US economy would not function - things like railroads and utilities. And those utilities have been heavily investing in renewable energy - you think that would be happening if Koch owned them?
One could EASILY argue that Buffett has been a lot better for the world than Musk.