I personally own 4 games that max it out.
You keep pointing out maxwell cards, but maxwell cards are not as capable as a 1080ti.
Its hard to explain but what I mean is this, for many many generations the most powerful gpu in that generation was never powerful enough at least without SLI.
Pascal was the first generation where a single card was powerful enough to play games at max resolution at 60fps.
Maxwell was never powerful enough to do this, even on launch day. Same with all previous generations.
I expect if a 1080ti is good enough now for your needs, it will remain that way until we see next gen consoles at the very least, which is predicted in 2020.
Nvidia know this as well, so they had to create a tech for consumer space which "slows cards down", hence RT. Because otherwise people would stay on pascal with it been "good enough", the exceptions been those who always want the latest GPU.