That's simply not true, at least in my case. As I said in a previous post, I have some pixel level discernment at 72 inches when viewing a 4k 55 inch display.
I don't have golden eyes. I'm in my 40s and I wear contact lenses and have some minor astigmatism. I doubt my eyes are nearly twice as good as the median.
A higher resolution may not be worth the tradeoffs in cost or other factors, but it isn't as pointless as you say.