Why? It is easy, intuitive, and used by millions of people.
Change for changes sake?
No wonder there is such a divide among users. I don't think age has anything to do with it though.
On Windows (and macOS) the desktop is fundamentally different, used differently, and is often obscured by your windowed content.
Luckly they managed to at least let users hide that in iOS10, but it's still a cesspool of rarely used apps.
Notifications are great for things that need your attention but the home screen becomes a little more of a seredipious view of app information that can increase the usefulness and engagement with an app
I would love to see the iPad interface evolve a bit and not look so much like my phone. I don't feel like they are using all that space as elegantly as they could be.