I don't know about intention, I mean e.g. the Health app is pretty clearly on the primary means of launching apps. I think it's more of a matter of people not actually sitting down to learn and explore their device.
Mind you I do believe Apple should release a proper manual. Barring that, there's a series of iphone books, websites and magazines that will go over these features over and over again.
If people don't invest the time themselves, why should Apple bother?
Also why is Apple and the iphone singled out? It's the same rhetoric for Windows, where the start button is a mystery to the computer illiterate.
TL;DR educate yourself or don't get an iphone.
I do believe text size should be an option for the first configuration though (and if you give your old phones to other people, do a factory reset and let them run through that initial setup themselves).
It gets complicated with apps though, designers often don't keep the variable size text in mind. That feature - at least when I looked into it a few years ago - gives you fixed text sizes to work, which is fine for default looking apps but a bit problematic when you're implementing a certain style.