A big part is also residuals, they don’t want to have to keep paying actors, directors, and others involved with production, after the fact on a losing property. If there is zero income there are zero continued payments.

In regards to your question about hidden methods to catch people, back before digital each film print sent to a theater had a unique “CAP Code” printed directly onto the 35mm film. This was a series of dots in a unique pattern that would show up several times on screen. So when a cam rip would show up somewhere this could be used to narrow down which theater it was recorded at and identify trends after several films.

I don’t know if this was ever successfully used to prosecute anyone though.

https://en.wikipedia.org/wiki/Coded_anti-piracy

Viewing distance and bitrate are most important. Sitting too close will make many things look bad.

For a 32 inch display you want to be 4 and a half feet back, and for a cinematic view you want 3 feet back.

https://www.rtings.com/tv/reviews/by-size/size-to-distance-relationship