More in the stream of neverending censorship bullshit from the App Store.
Apps aren't even included in "backups", so restoring a device from backup won't actually put it into the state it was before: you get the current versions of any apps (if they are even still available, sometimes they aren't) re-downloaded at time of restore. This is, of course, contrary to the entire concept of what a backup is for.
Of course, you can't download any apps at all without an Apple ID, and also providing your unchangeable hardware serial number to Apple (transmitted when you launch the App Store like a supercookie). You also can't get the Apple ID without providing a telephone number that can receive SMS, so you basically have to dox yourself to restore a working backup.
I've had every single iPhone that has ever been produced (except the 3G - I went from 1 to 3GS), but I'm fairly confident I have purchased my last one.