That's a really alarmist (and counterfactual) way of framing this.
Yes, if you change computing platforms, you generally need to replace software. OH NO. I don't see a need for regulatory intervention based on that.
Deciding to ditch the iPhone for an Android has utterly no bearing on your ability to watch TV or movies purchased from the iTunes store. You can still watch those on an AppleTV, on a Samsung TV, or on your laptop. And obviously on your iPad if you have one of those.
Tracks purchased from the iTunes Music Store are yours, period. There's no DRM, so anything that can play AAC will play them fine. You don't lose those if you ditch the iPhone.
However, Apple Music is a distinct thing. It's a subscription service like Spotify. If you stop paying for it, you stop getting access to the music you acquired with it. This is neither nefarious nor exploitative. You need a device supported by Apple Music, but it works on Windows, so not seeing the problem here, either. (Though I should note that I wouldn't see a problem even if Apple Music worked only on Apple devices.)
Apple is a rounding error in digital books, and I know nothing about it (mostly a Kindle guy). However, if I decide to banish Amazon from my life, I'll lose access to Kindle books I "bought" from Amazon. That was part of the bargain at the time.
>There should be regulation requiring companies like Apple to allow users to sell the apps and other digital content they’ve purchased to others, to allow people to set their own default apps on their own devices and to not hamper the efforts of others to provide interoperability with other devices.
How far does that go? Would you insist on the right to do the same to any computer-controlled device you purchase from any vendor?
Because that seems bananas.