(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)
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.
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.
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.
