Love this topic. During Covid I had just gotten setup with my first 4k TV and UHD player, so getting into collecting 4k Blu rays definitely became a comforting "embracing my impending middle age" hobby (lol). I agree with what most of you are saying. I think at the current rate things are going, it will essentially become an equivalent vinyl-- though that's not necessarily a bad thing altogether. Granted, an increase in pricing is unfortunate and it's why I don't really buy a ton of vinyls anymore, although I feel like I should more often to support my favorite artisrs. The difference there however is that I primarily tend to listen to music on the go-- in the car, at the gym, on headphones while working, etc. With movies, it's a couch activity whether it's on streaming or a physical copy. Owning the physical copy becomes more about embracing the act of curating your own personal collection. There's something that just feels more fun and intentional about buying a movie and then setting aside time to watch it, vs. the sort of numbing process of browsing a streaming app for 20 minutes trying to decide what to watch. Then there's the purist aspect of having unrestricted access to the best possible version of the film. A great 4k transfer of an older film in some cases can be some of the most stunning things you'll ever be able to see on a screen at home, so it's also a fun way to invest in either revisiting old favorites with fresh eyes or checking off classics that you've never seen.
I get that space is a consideration for people, but I think there are creative solutions to where it doesn't have to be a dealbreaker. You can always get a CD book and get rid of the boxes. I've seen other creative solutions where people keep the box art booklets within the binder too. For me, 4-sided rotating shelf was a pretty good solution. Like
@Mani-Man said, I just enjoy having movies on the shelf, it's a comforting aesthetic for me to have in my space. I don't have an insanely large collection, so as of now it's able to store all my 4ks and Blu rays, video games, even a bunch of my old CDs/DVDs/VHS tapes while leaving room for the collection to grow, just sitting in a corner. Eventually I'll have to phase things out, but I see that as just a normal part of life-- there are always cycles of accumulating junk and then (hopefully) decluttering.
I don't think it's gonna die anytime soon-- even as a niche, there are enough passionate collectors out there and I think with the major retailers dropping out, it could lead to a golden age for the boutique vendors who are going to keep the torch alive (if it's not there already).
As with movie theaters though, I think the ultimate key to sustaining it is studios continuing to make films that are truly worth paying money to see/own. As long as they can do that, there's a lot of money to be made with those revenue streams compared to a movie that goes straight to streaming.