I'm honestly wondering if I'm an outlier and may have better than 20/20 vision. I would think it's pretty rare, but I have had people comment on my vision before. I work on a 17" 4k laptop screen with tiny text no prob.
At least with the 4k OLEDs, you are also getting HDR, way better contrast ratio, better colors, etc. So, you'll notice that, even if you don't notice the resolution difference.
I am excited to see Xbox support HDR. I just hate to see all of this extra hardware dedicated to resolution, when there are so many things that it could be put to.
However, all else is rarely equal, and 4K TVs now have lots of other features and technology that make them just better (prettier) buys in general.
[1] http://s3.carltonbale.com/resolution_chart.html