The first thing that comes to mind is that any responsibility to the game playing audience on the part of any developer should begin with the design phase of the game, and end when the product is shipped. Now, obviously that just doesn't fly anymore, as it might have in the days of coin-ops. These days we have the MMO, which is a genre of game that one might consider to be continually in development. As such, the developers open themselves up to constant criticism from the game's audience. So it might be said that the developers owe its audience the willingness to listen to gamer feedback, and the promise or ability to try to incorporate some of the more inspired bits of advice.

But in this case, is that all? With the fairly recent closure of Hellgate: London and Mythos (I shed a tear), the subject of disenfranchised players comes to mind. Mythos was free, but there were undoubtedly some paying players in H:G, and some of them might even have selected a payment option that encompassed future months for a lower price. But monetary issues aside, do loyal players deserve something if their favorite game goes away? Does that extend to making game assets available for anyone who might want to try hosting the game on their own servers for free? After all, if there is no game, there's no more need to protect intellectual property, is there?

Furthermore, would the new hosters then owe the remaining audience anything other than providing gameplay? Would it be enough to keep the game running? Does the game then become a sort of open-source project? Does the game need to evolve, with new items, adversaries, storylines, etc., or should it be kept as-is?

This will probably never happen. There are likely all manner of legal issues in place that prevent the game in question from falling into the wrong hands, as it were. This makes me think that any such conversation concerning ethics is premature, and that the lawyers care nothing for the concept of gamer-related responsibility. But if you ask the developers themselves, they'll probably say that what they most want is to make the best game they can, and that they want the audience to love it. But that in itself is a type of responsibility -- trying to gauge the will of the audience, guessing what might go over well, and how best to implement it. But until they get feedback, the developers are only creating for themselves what they like, which is the best way to create quality, in the end. Put into the world what you would like to see, and let the audience for the game find you.