Do you watch those movies / series more than once? I have always thought of Blu-ray disks like books. You consume it and then lend it to a friend. I get that this is not what the media companies would want, but purchasing media/books and not using them more than once just feels wrong.
My rule of thumb has generally been "if there's any chance I'll want to watch the movie more than once, I'll buy the blu-ray."
Until about two years ago, I was happy enough to pay for two streaming services (HBO Max and Hulu), along with Amazon Prime, and I treated that like my "rental store". The first viewing would be to see if I like the movie, and if I did then I would immediately order the blu-ray.
Now I've canceled all my streaming services because I don't want to pay for a million of them.
Just a note, I will very frequently put a movie or TV series on in the background while I work on other things, probably even more frequently than I turn on music. I just like having noise from a movie or show that's familiar for me.
It's just gotten farcical. I am not opposed to paying for my entertainment, but I'm not going to pay in perpetuity $15 a month to ten different services when they will happily delete the content I like for a tax writeoff and replace it with reality TV. I haven't even used Amazon Prime streaming since they started forcing ads on us.
It's how I justify running a server 24/7; the increased power costs are lower than what I'd need to pay to have all the major streaming services every month.
I am slightly embarrassed to say that yes, I watch movies over and over. All of them off of a shared hard drive using Kodi on an Apple TV to watch.
I recently through away all my CDs, DVDs, and BluRay after carrying them from apartment to apartment for years (in notebooks) and never once opening them during those years.
As for the embarrassment. I get from some POV it's a waste of time but I easily have a list of ~400 movies all of which I've watched 3-20 times each. Examples might be a movie like The Matrix I'm sure I've watch 10+ times. A movie like Harvey, 2 or 3.
I also watch movies multiple times! Typically it's several months or years apart, but sometimes it's more frequent. I remember the first night I saw Primer, right after it ended I started it all over again because I needed to understand. Unfortunately, the second watch did not provide as much clarity as I was hoping.
I hated Primer, feels intellectually dishonest. It tries to present itself as story with consistent mechanics, then near the end gives up and it's like: this is time travel story, so we need to throw in some paradox.
I watch movies while doing other things (cleaning the house or certain design tasks at the computer) which makes it very easy to watch them again! I go through them quickly and will tend to go back to them after about a year. I recently watched all of the Mission Impossible movies over the course of a few days.
I only buy the bluray if I've already seen it and know I'd want to watch again when I receive it. Keeps me from collecting stuff that doesn't get watched.
I loop through the collection by putting a watched disc back in a separate spot until I've gone through them all and then start over.
I buy Blu-ray disks exactly because I watch most things only once, because the one time I watch them I want to watch them in the best quality available. What you do with the Blu-ray after watching is a different question.