If I were Apple I'd simply make a time capsule that holds lets say three hard drives and has an iTunes server daemon on it which you can access the front end from using your Apple TV. It would sell like hot cakes. People don't want to have to have a dedicated computer just to run iTunes.
The whole issue with iTunes is that it's far to monolithic in nature and it's accumulated too many things.
At first glance its an App Store and music/video store, the next thing you know it's a media player, then it's the back end for a home theatre, and then to top that off it's a backup utility, while also trying to be a server in and of itself.
It's a mess as a program entirely, it needs to be torn apart and rebuilt again, the HTPC back end should be a daemon that can be run in and of itself anywhere on a headless server, or on a NAS box such as a time machine.
You shouldn't need an entire computer in and of itself just to run an iTunes server, it's a waste of space and resources and I don't even want to get into the programer side issues of iTunes working with an app where the ability to add new features is lost among a growing list of complexities and annoyance, where bug fixes become a nightmare and resolving technical issues becomes horrendous.
iTunes simply tries to do too many things and in the end it just doesn't really do any of them well to any particular extent. It really needs to be broken down into a bunch of microservices and daemons.
