Is it normal that the thought of buying older movies on 4k seems pointless?

Not all remasters are created equal.The new 4K artwork (cover) is also hideous compared to the original artwork.

Really high resolution... Doesn't work unless you've got the TV, or screen to go along. 4K TVs and screens were very expensive, but nowadays you can get a 4K tv for as little as 500 bucks.
I paid over 2 grand for mine - fml...

If you play a 4K movie on a screen that's say only HD (1080p by 720p), you're not gonna get anything out of the 4K.
You need a 4K screen to get the full experience.

But I believe it's worth it. A lot of old movies were shot in very high resolution, even if the initial releases weren't that high-def. Movies shot on film had a higher resolution than the cinemas, or TVs they were played on. Then comes digital restoration in play. Mending various bits in the movie to make it look as good as possible.

Resolutions of around 4,000 pixels.