This is so true. It's a damn shame that the extra 4GB of RAM seems to be very under utilized and unless you're MS 1st party it seems extremely rare that devs use higher res assets. Most devs seem cater to the lowest denominator (PS4 Pro) and just bump the res and call it a day.
Lowest common denominator is the base Xbox One not the Pro, they are upgrading based on the base platform not the competitors machines. Mark Cerny said the reason the Pro didn't get a big memory increase was because it can cost millions of dollars to create those higher end assets and while some seem to think every game has them that's obviously not the case or every PC game would have a super high res texture pack. There is no reason not to add those higher end assets if they are just sitting there waiting to be used, clearly there is more to it than some assume. Just increasing the resolution already brings out more detail in the textures currently being used anyway.