Interesting purely mechanical design. Our first remote (that didn’t have a cable connection) used sound as well, but it was battery powered and as a kid, I could hear at least some of those sounds. It had way more than just 4 buttons though, maybe the mechanical design hits a limit there at some point (or electronics just got cheaper).
Every phone with removable I had had a pretty flimsy back cover that started to crack during the lifetime of the phone. The gaskets started to go or weren’t even there in the first place, so they weren’t even splash proof (so better avoid getting rained on or even get sweaty).
And none of my phones ever required a battery replacement during its life time. My Galaxy S4 mini ram out of support, I flashed it with a custom rom then that stopped being supported (and the hardware really couldn’t deal with later android version). My Fairphone 2 started crashing regularly which ended its life. And my iPhone 6s had a solid 5 year life with no battery issues before I retired it to get a better camera.
So for me requiring every phone to have an easily replaceable battery has pretty much zero upsides but a bunch of potential downsides.
Almost all of those are pretty niche problems though. Which explains why they just aren’t a high priority for manufacturers.