I own a 1080ti and there was recently a massive update to Allan Wake 2 that made it more playable on pascal GPUs. Digital foundry did a video on it: http://youtu.be/t-3PkRbeO8A
I don’t know of any current game that can’t run at least 1080p30fps on 1080ti. But of course my knowledge is not exhaustive.
I wouldn’t expect every “next-gen” game to get the same treatment as Alan Wake 2 going forward. But we’re 4 years into the generation and there has probably been less than 10 games that were built to take full advantage of modern console hardware. My 1080ti has got a few more good years in it.