I honestly think it's far more likely that game developers of the future will make use of virtual reality to create realistic games, rather than photorealistic graphics rendering. The latter would be hugely expensive both in computational power and manpower (although procedural generation could eliminate much of the latter, it still depends on your goals).

Also, the great thing about games is that they're not necessarily meant to conform to reality as a standard. If you want photorealistic graphics, go outside. A game that relies primarily on its graphical fidelity is doomed to obsolescence, but a game with good mechanics and an aesthetic is potentially timeless.