> I can’t think of a single WASP billionaire though

Gates, Buffett, Musk ... all spring to mind.

White certainly. Anglo-Saxon doesn't mean much more than "of western/northern european ancestry" any more. Protestant as much as any other non-Catholic Christian sect.

But WASP doesn't mean literally what it means any more, so maybe I'm missing the reason you overlooked the most famous modern American-citizen billionaires?