It's pretty clear that 5k / 218ppi just has no significant market appeal at this point
This is apparently true, and it's baffling. I was able to pick up one of the now-discontinued 5k PC displays a few years ago, and it's fantastic in Linux and Windows with 2x scaling.
I think this is just because 4k has been settled on as the standard, and the difference between 4k and 5k is too small for most manufacturers to bother offering both.
You'll likely see 8k as the next common step up from that (it's already happening with TVs). Who knows, maybe we'll have this same conversation again then because Apple will release a 9k display at that point.
I’m trying to make a 32” 4K work for me, and Windows’ 125% scaling is hot garbage. Macos is slightly better, but it’s still obvious it’s not an integer multiple of native.
This was absolutely true five years ago but there's been so few recent attempts since GPUs, Windows/Linux, and fast connectors have improved that I think this has become an apparent axiom when it's really more of an untested hypothesis.