This is actually a big part of the reason why I'm in favor of unified digital distribution platforms like Steam. Realistically, the industry isn't going to go back to the days of selling games as unsecured CDs, so the linking of purchased games to cloud-based accounts like that is as good as we're going to get. It avoids a lot of the major issues with DRM relating to number of installations if you can always install any game you've linked to your account to any computer where you've downloaded the platform and logged in (as well as allowing you to progress saves on multiple machines), but you also have the fallback of being able to go offline and still play installed games even if something happens.
The ideal, I think, would be a paradigm of multiple relatively equal and consumer-friendly DDPs without exclusive titles or walls around multiplayer between platforms. DRM's not going away for the bulk of the industry, so the aim should probably be to reach a point where the major developers and publishers that want it will be satisfied with a solution which has the smallest possible impact on non-pirates.
I mean, I'd love a return to the old way of things, but it ain't happening. The copy of Tiberian Sun I've got these days is running with a genned key (because second-hand in a ragged paper sleeve from a used electronics store, natch), and I can just imagine the horror of large companies if their modern games could be shared like that between everyone who knew someone with a link to a torrent with the game files and a CD key generator.