I get TV shows in 720p and movies in 1080p. On my 75 inch TV, it's hardly noticeable unless I do a quick switch back and forth between a 4k and 1080 source of the same movie.

That's the thing. I can totally tell the difference between 1080 and 4K. But not once have I been watching a 1080 blu-ray and thought it would look better in 4K.

Most TVs have a ton of filter on any movies which you want to watch on them. You basically won’t enjoy anything how it was intended. I specified monitor and good color gamut for a reason.

I willingly avoid 4k media and 4k tvs. 1080p is fine, if the movie suck the additional pixels won’t make it any better anyway.

And 1080p os faster at everything: downloading, playing, streaming…

It’s exactly 30 seconds to start to play anything nowadays. Popcorn Time’s one main feature is to make it unnecessary to wait, but nowadays you can do this with anything basically.

Lets say you want the IMDB top 500, most of those will not have a scan that is better in 4k than 1080 or even normal DVD (480p). The ones that do (like 4k77) are probably highly specialized.

What is the highest res 2001, godfather, solaris, alien rip that you can get?

3 out of the 4 films you mentioned have 4K Blu-ray releases

That doesn't mean they have a scan that benefits from 4K.

That also doesn’t mean they haven’t have a scan that benefits from 4K, but it’s a rather an indication that they benefit than otherwise.