I wouldn't qualify them as knowing the basics. I think they're musical geniuses.

OK, it was a bad example. None of them seem to have a formal grounding in music theory, except Chad Hugo who dropped out of college before finishing.

I guess, at best, you're making the argument that you don't need to go to conservatory to make pop music. While true, I think it's fair to say these guys are all really musically minded. In particular, Rick Rubin and Pharrell cut across genres really well (from rap to rock and stuff in between), which is decent evidence that they're not just lucking into popular singles.