You are correct in that a great deal of people aren't fussy and will watch things in streaming quality and not care. But like you when you see what things should be like you can tell there is a difference .
I was sceptical once - was happy with just dvd versions of movies (still infinitely watchable on 55"+ TV screens. But then I saved a bluray of one of my favourite movies and saw how things can look on bluray. At that point I only had a few bluray titles (purchased wayyyy back during the ps3 era). Then I just went nuts and expanded my bluray collection. And then I discovered 4K and my mind was blown again
Dumb question
Does a 4K BluRay play on any BluRay player?