Sorry you're right. 4K Is run of the mill now. 5K is not quite. But the point still stands, technology improves. It only needs to improve to a certain level before it goes beyond human perception. That will happen in a few years.

Any efforts trying to adapt to the limitations of current technology are wasted.

Here's a 4K display from Phillips for $235 https://www.amazon.com/Philips-276E8VJSB-3840x2160-UltraNarr...

Edit: and a DPI calculator and reference. Notice all the old low-res displays and how most of them are behind us. https://www.sven.de/dpi/