I have come to the conclusion even among the really dedicated folks to enjoying the best they can at home Variable immersion isn’t high on most peoples list. So we are a subset of a subset within home theater.
That's for sure!
It looked a while back like the "beyond 2:35:1" systems - e.g. which could expand for IMAX and generally use zoom/masking for more flexibility - were going to start taking off. As in some commercial AV companies were starting to push the idea. But from what I saw the commercial versions were wildly expensive - for rich guys-who-cared. I haven't followed the latest trends for a while, but I wouldn't be surprised if it petered out.
But, as I say, I still get a kick out of the flexible system as do my guests. My room is always packed for watching the UFC and I usually start with most of the fights at an average size - say 102" to 105" 16:9 diagonal. But for the big final match I often press a button and the image/masking zooms the image far larger, moving in to more IMAX-like immersion, like we are "there," and that's always fun!