I’m one of them. It mostly comes down to, is this movie a visual masterpiece. If no, I get a DVD, usually. Depends on price. Sometimes a Blu-ray is cheaper cause of a sale or someone selling a cheap copy. There’s maybe a handful of movies I own where Blu-ray is a must.

I own nothing in 4k despite having a 4k TV. The difference is miniscule to me. At least at normal viewing distance.