Haven't read the actual terms but I wouldn't be a bit surprised if Steam required publishers to make games purchased on steam available to the account holder perpetually regardless of what happens to the publisher. Some publisher says oh we're gonna yank this? That would make Steam look bad, and they have enough clout to just say no you can't. Publisher goes out of business and you just don't get any more updates. I suppose I could see Steam pulling a game and even auto-deleting it out of my library in some situations, like if there's a major security flaw.Crypto maybe could have been a no trust licensing persistance/resales algo in there, but steam is so strong that persist should be quite ok, virtually no game has been removed from it yet (from the buyer point of view), the way persistance has issues (third party lauincher, OS/drivers, servers and so on) would all be there with disk.