Yes this is all very true, and I have my own limitations of course; I don't fret over $200 cables or any of that. The truth is that for some movies for the reasons you already stated there's no difference worth noting because the problems are with the grading, lighting, or some other production issue.

In some cases though I think with a decent OLED most people would tell the difference. A movie like Sinners in UHD from physical media gives you something much closer to a good theater experience than the same movie compressed and streamed. Would I say no to watching Sinners at a friend's place through streaming? Heck no, it's a great movie regardless, but when I have a choice and the convenience... I'd pick the disc.