(Note: This isn't because Apple is without faults. iOS and macOS are both a mess right now, and iPadOS is even worse. I just think that Android is worse than that, and I know many, many Apple users are in the same boat)
OEMs and carriers shove in their own apps (Samsung is especially bad about this: I don't want two apps for photos, and files, and messages, and calling, and browsing, etc etc). You can (sometimes) disable or uninstall them, but they can pop up again after updates, and I don't want to have to clean up my device just to use it.
And visually, apps look and feel radically different, all over the place. There are apps that still look like they're running on Jelly Bean, apps that use modern material designs, apps that roll their own UI, and web apps in wrappers. Every new app I have to learn how to use it. This is an occasional problem on iOS, but it's very rare compared to my experience with it on Android.
The problem is that people don't really have choice. Both iOS and Android have positives and negatives, and often those positives and negatives are not the same. Choosing one or the other is going to have you missing some positives you want, and taking on some negatives that bug you.
If this was just the nature of how things have to be, I'd be more sympathetic. But the real reason it's this way is due to anti-competitive behavior on the part of Apple. There are no technical limitations; it's just their business model to restrict what people can do with the device they've bought. There are certainly some valid security reasons for doing this in some cases, but most of it is just to protect their revenue streams.
Android is fine. It has some downsides vs. iOS, and some advantages. But that isn't the point. The point is that to make a new smartphone OS (or even one that's based on Android, but is independent of the Google ecosystem) that can do everything Android and iOS can do is an undertaking that few would even bother to take on. That's not due to technical challenges, it's due to market barriers that Apple and Google have erected. (IMO, the sorts of things that we as citizens in a healthy society should not allow corporations to do.)
And those that (sorta?) do try to make a competing OS, like LineageOS, GrapheneOS, CalyxOS, etc., end up with far less-capable phones than a Google-blessed Android phone. (And when most/all of those capabilities are present, it's through brittle hacks and compromises that basically turn the phone into an imitation of the Google-blessed phone, with many of the downsides intact.)
Put another way, it's not Apple's or Google's responsibility to make things more competitive, but it is their responsibility to not make things anti competitive, and it is their fault when alternatives don't exist because of their anti-competitive behavior.
As a few examples
* (almost all) bought apps don't transfer
* bought media (music, etc) and how that integrates into the software
* icloud and other account services
* replacing your phone + laptop + watch + IOT devices which may all be in the apple ecosystem.
So one can easily see how folks who have bought in are willing to put up with user-hostile actions.
Of course, Apple is not the only company that uses integration as a way to retain customers. However, from personal experience, I feel Android is a bit more open (at the cost of a more fractured experience). I can definitely understand the pros of not having to deal with carrier installed garbage when purchasing a device.
There's no technical reason it needs to be this way. Apple just prefers to be anti-competitive and increase their profits, than to give their users the as-close-to-ideal experience they want.
