To those making this argument, all I can say is this: with day-one patches and online passes, you already don't actually own the game, you own a piece of it. And for the time being, a piece is still better than nothing. But in the near future, Microsoft's original proposition with Xbox One will become more and more of a reality.
As for the delisting issue or having your content at the mercy of a platform holder's future in the industry, yes, it's a terrible proposition. Equally as terrible as, say, losing a game, having it stolen, having it burn down in a house fire. The only difference is that you can't blame those circumstances on someone else, but those unfortunate circumstances happen with far more regularity than the collapse of a corporation. The point is that buying physical does not make you unassailable from misfortune and it's wrong to kid yourself to the contrary.