Because most of the users don't know how to turn that shit off in AAA games. It's often just defaults to being on, no?
Also I thought DLSS is supposed to help with underspecced PC-s to help run modern games. So this is a self burn in a way, either RTX cards are not as performant as hoped, or the AAA games sector is just fucked, as they cannot for the life of them pump out an optimized game.