That's exactly why Magnus is now championing Free Style Chess, originally promoted by Fischer: you randomize the starting position of the pieces, which makes traditional opening theory useless. That cuts away a lot of the memorization and introduces a lot of new creativity.

It's not entirely surprising that both of these world champions saw that as a way to keep the game interesting.

Something else that Magnus sometimes does, even against fellow grandmasters, is play a completely ridiculous opening that's obviously bad. But more importantly, it's different, and all the existing opening theory goes out the window.