I'm inclined to think most of these guys don't get in slumps as Erik suggested.
Its more along the lines of everyone on Tour is crazy good, and from time to time someone gets hot, wins a bunch, and that's that. Golf is littered with these kinds of players, like Hunter Mayhan, Chris Demarco, or Anthony Kim to name a few. Even someone like John Daly was lucky enough to get hot a couple of times despite his complete lack of training regimen.
Its 100% plausible that someone like Scottie Scheffler, the latest hot player, will be 105th on the money list in just a couple of years from now.