What remains to be seen is how this plays out on Windows.
My bet would be that iTunes/Win32 will be replaced with web apps, requiring Encrypted Media Extensions (EME) for DRM.
iTunes for Windows currently relies on QTML ("QuickTime Media Layer"), which is the porting layer that the QuickTime team created to bring QuickTime (and QuickTime Player, etc.) to Windows. I'm sure that Apple would love to kill QTML as soon as they can.
I'm also reasonably sure that Apple isn't interested in Universal Windows Platform (UWP) development. That leaves web technologies as a likely solution, which (based on iCloud's web apps) Apple's pretty good at, and seems to be betting on in earnest.
That does not allow managing your iDevices... while I believe there is some html5 way to access Bluetooth, I rather hope they won't ever implement USB...
Luckily, they aren’t that insane:
"Attacks against USB devices
The WebUSB API does not even try to provide a way for a web page to connect to arbitrary USB devices. There are plenty of published attacks against USB devices that makes it unsafe to allow this.
For this reason, a USB device can define a set of origins that are allowed to connect to it. This is similar to the CORS mechanism in HTTP. In other words, WebUSB devices are associated with a web origin and can only be accessed from a page from the same origin."
Given that a computer isn't really necessary to operate an iOS device these days, could Apple just cancel the Windows version of iTunes without a replacement?