Horsepower that 'would' enable higher frame rates than 90fps enables the ability to knock the pixel density up.

The GTX1080 (and Ti especially) can effectively run at 4k configurations and downscale the output to the 1440p resolutions that the headsets run at. For flight Sims and racing Sims this does make a welcome difference as the text on HUDs and dials change from slightly blurry to very clear.

Personally, I think it's the next gen headsets with 4k displays that will really give us what we need however the issue is still the GPU. Although the 1080ti comes close and can reach 60fps in most (but not all) games the VR headsets really need that consistent 90fps frame rate to keep everything nice and smooth. I think we're still a generation or two away from that so another 3-4 years.