Comment by joshuaissac

There are services like Movies Anywhere and UltraViolet (now defunct) that store a licence when the user purchases one from an in-network licensor. Then the user can access the content via any supported platform.

The problem is that these are not legally mandated, so they can shut down (as UltraViolet did). If the ability to move the licence to another platform is mandated by law as a condition of continued copyright protection, this problem would largely disappear.