Can I stick my hand up and point out that logging on to the server is a form of subscription? This method looks so much like any other subscription based software that's going around (Adobe CC, Microsoft Office365.) Whether or not in name this is in fact signing in to a subscription. Because I can go to any one of your PCs and if Elite Dangerous is installed, I can log on to it with my password and play my commander, right?
Microsoft has done with keys to unlock their software years ago. Hence Office 365 is DRM free - you can download it and install it anywhere, but you have to log in to use it properly. That's subscription, not DRM.
We have a winner \o/