>"So by most you mean 51% of the 7 billion or so out there?"
Reasonable setup- 60" TV viewed at 8 feet:
No, by "most" I would estimate 75% of people off the street would not be able to tell you they were watching an upscaled DVD on that setup instead of 720P or 1080P (without showing them that) and be perfectly happy. Maybe 50% of those 75% would probably still not even notice a difference if you flipped between the upscaled DVD and a 1080P source in that same setup.
And I would estimate 99% of people off the street would not be able to tell any difference between 1080P and 4K in that same setup- even when flipping between the two. The number would be higher for really large TV's, or really close viewing, but it will still be an insignificant number.
Now, the results for the typical Slashdot demographic? The numbers would be much further along the "I can tell" scale, but I bet not as much as you might think.
Resolution is a rapidly diminishing return once you reach "very good". It is the same insanity of putting a 2K display on a 5 or 6" phone. It is WAY beyond the human eye resolution discrimination for any typical person held at any reasonable distance (like 12 to 14 inches). So rather than being a useful feature, it becomes more of a marketing gimmick- a spec just to sell devices to consumers that don't know any better. The net effect is it just pushes up the price and places more demand on the battery.