Well, here's the legal problem: suppose that the company does have a reason for closing a game, but either can't tell you or it just doesn't satisfy you.
Let me give you an example. Suppose that the game you are playing is the brainchild of its brilliant development team, and the team is going to a convention and their bus crashes and half of them die. Their company, in respect to their employees' families, doesn't release the details to the general public, but they don't feel that they can do the game justice without their beloved dev team, so they feel compelled to sunset the game. Obviously this didn't happen with CoH, but suppose it did happen to a game. Having a clause in the license that allows the company to do that would be legally prudent.
Now, for that matter, NCSoft did give us a reason for closing CoH. It was for a realignment of company intentions. Those intentions may include trade secrets, so it would be potentially financially disastrous to let other companies know what they're working on. It's just that you, the player, aren't accepting such a crappy answer (and with good reason!). But suppose that it had been for a good reason, as in the above example with a dead dev team and wanting to protect their employees' families; how many gamers would still be unsatisfied ("why can't you just put the game on life support")?