The main problem is that they update the software.
The vast majority of "new features" is not useful to a user - with Mac OS, I can't think of a single useful feature since Snow Leopard. That was a very long time ago. Snow Leopard made everything faster and cleaner, and it was great. Since then - an endless stream of forgettable and never-used added features.
So a lot of this software falls into the "it's different now, without actually being better" category.
iOS as well, although iOS 15 had text detection in images, which is both super cool and very useful - other than that I get uglier notification boxes (huh??) for no reason. Why did they get uglified? What do they do better now than before?
Updates should
- Fix bugs
- Fix security holes
- Support new processor or other hardware
- Make things faster
- And very very rarely, when there is a clear advantage, update how things work. But mostly, it should not update how things work, since that is most of the time just confusing, without being better, so updating software becomes a hassle.
The main issue in iOS and Mac OS is a software team that seems to be rewarded for adding as much stuff as they can, and changing as many things as they can, in typical corporate BS world, so they can show their managers a long list of things they did as proof of their continued employment, and when the whole company does that, bad software decisions are made.