I have been gaming on 4K for nearly 3 years now. Not half as hard as people make it out to be imo. I do not use aa which saves fps, also turn off all the undesirable effects like depth of field, motion blur etc and that brings fps between 30-60 in most recent games. 99% of all games made I can play 60fps+ anyway
Worst case scenario all one needs to do is do the above, in addition to dropping from Ultra settings to Very High on a few settings and it will still look better than 1440p with everything on
With Volta 4K power will be here imo. But there will always be a handful of people who need minimum 100fps in which case they will have to wait another 2-3 more years.
It is all relative end of the day.

Worst case scenario all one needs to do is do the above, in addition to dropping from Ultra settings to Very High on a few settings and it will still look better than 1440p with everything on

With Volta 4K power will be here imo. But there will always be a handful of people who need minimum 100fps in which case they will have to wait another 2-3 more years.
It is all relative end of the day.