Assuming the product companies accept the plateau on resolution (I agree it’s likely), there are many ways to exploit the other stuff. Colour space, tacling each type of compression artifact, additional channels (probly not long until we have HDR RGBW), etc etc and those will each come with their committees made of patent-hungry companies seeing non-encumbered encodings as “undesirable”
As it becomes cheaper to capture and process higher res content, we're bound to push it to bigger displays (VR included). I guess the human eye will be the limit when we're at retina levels of DPI on a sphere.
We'll see how much 360 content shows up, but the size gap is so big it basically needs to be handled entirely differently. A 16x9 screen, 40 degrees wide, is only 2% of a sphere.