I don't know... my lock screen has a camera icon always visible. When you tap it, you get an isolated camera mode that only shows you photos taken in that session. That's the standard screen now, so I think Apple is doing okay on the discoverability front (for that specific use-case -- possibly the only case where something is discoverable in iOS).
But I still don't know how to take a picture on an Android phone. I have no idea what the Android virtual buttons mean or what they do at all. With similar logic, my wife still has an iPhone with a physical home button because she doesn't like my (now old) iPhone with the "swipe up" home motion. She doesn't really want to learn how to use a new (ish) gesture.
And while I'm on a roll... I also don't understand the buttons on Playstation controllers, preferring the direct lettering of the Xbox or Switch.
We are all ultimately creatures of habit.