Very slightly unrelated, but this trend is one of the reasons I went Android after the iPhone removed the home button. I think it became meaningfully harder to explain interactions to older users in my family and just when they got the hang of "force touch" it also went away.
First thing I do on new Pixel phones is enable 3 button navigation, but lately that's also falling out of favor in UI terms, with apps assuming bottom navigation bar and not accounting for the larger spacing of 3 button nav and putting content or text behind it.
I am firmly in the “key UI elements should be visible” camp. I also agree that Apple violates that rule occasionally.
However, I think they do a decent job at resisting it in general, and specifically I disagree that removing the home button constitutes hiding an UI element. I see it as a change in interaction, after which the gesture is no longer “press” but “swipe” and the UI element is not a button but edge of the screen itself. It is debatable whether it is intuitive or better in general, but I personally think it is rather similar to double-clicking an icon to launch an app, or right-clicking to invoke a context menu: neither have any visual cues, both are used all the time for some pretty key functions, but as soon as it becomes an intuition it does not add friction.
You may say Apple is way too liberal in forcing new intuitions like that, and I would agree in some cases (like address bar drag on Safari!), but would disagree in case of the home button (they went with it and they firmly stuck with it, and they kept around a model with the button for a few more years until 2025).
Regarding explaining the lack of home button: on iOS, there is an accessibility feature that puts on your screen a small draggable circle, which when pressed displays a configurable selection of shortcuts—with text labels—including the home button and a bunch of other pretty useful switches. Believe it or not, I know people who kept this circle around specifically when hardware home button was a thing, because they did not want to wear out the only thing they saw as a moving part!
I had the same story, which is why the last phone I got for my grandma was an iPhone SE (which still has the home button). This way, no matter where she ends up, there's this large and obvious thing that she can press to return back to the familiarity of the home screen.
I am the same, long time Android user and when I borrow my wife's iPhone it is an exercise in frustration. Interactions are hidden, not intuitive, or just plain missing.
Now that Pixel cameras outclass iPhone cameras, and even Samsung is on par, there is really no reason to ever switch to the Apple ecosystem anymore IMO.
I still have my iPhone with home button. That’s also a solution ;-)
Similarly the disappearing menu items in common software.
Take a simple example: Open a read-only file in MS Word. There is no option to save? Where's it gone? Why can I edit but not save the file?
A much better user experience would be to enable and not hide the Save option. When the user tries to save, tell them "I cannot save this file because of blah" and then tell them what they can do to fix it.