I think your right that's its a lot easier to monetize a pvp game than a pve or single player game (especially these days when players expect ongoing support even for single player games) but I think your comparison is a bit unfair when it comes to creativity to actually create the game bit.

The battle Royale (and previous trends before it like bomb defusal, team death match etc) are mature game modes with well understood mechanics and limitations. That does indeed make things a lot easier to make. But it's also a lot easier to push out yet another assassins creed game than to create an interesting single player game. I think creating a novel pvp game is just as difficult as a single player or pve game.

I think triple a games in general suffer from a lack of creativity due to a huge aversion to risk and a misallocation of resources to asset development rather than gameplay mechanics. And unfortunately creating a successful indie multi-player game is insanely hard because of how robust the player vase has to be.