Honestly, while I do hope Steam takes the game down, to me it's your responsibility to make sure that you can run the game, which is precisely what this is. The game runs fine, but the servers are down and it's a multiplayer only title. I don't consider this too much different than buying a game that you don't have a good enough graphics card to run.
To put it into perspective, you can still buy copies of ?Battleforge? on E-bay, even though 90% of that game is multiplayer and the servers have been down for years. So if someone buys it from there and then realizes that the servers are down, I don?t have a ton of sympathy for them.
It's also worth nothing that, sometimes (thought very rarely), games servers actually get re-established. This happened with Myth: The Fallen Lords and Myth 2: Soulblighter, where Bungie shut the servers down, but a group of dedicated fans managed to open up new ones.