Sure you could require them to inform the user. It would still require a change in law. I would personally stand against it because what you propose is the bare minimum needed to maintain legal status while maximising corporate comfort and minimizing user experience. It would be a law purely made to help companies exploit users.
Companies shouldnt be allowed to take completely absurd counterproductive (in the greater sense) measures just for the 0.01$ higher profit. If companies would behave like people in maintaining a healthy relationship with the law, this wouldnt be a problem. Fact is, many companies do everything in their power to get as close to the fine line separating immoral from illegal as possible to maximize profit (also more often than not straight illegal but hard to prove).
You know about squatters rights? Its the same phenomenon, except imagine 10% of the population doing it. Im pretty sure the law would change in a heartbeat. Companies have no moral compass, no shame or sense of dignity, thats why they need especially strict and explicit laws keeping them in check.
Also, to your last point: You would not be prevented from buying it. You would simply buy it under user friendly conditions. Noone would stop you from just not playing the game after a year if thats what youre concerned about. I dont see why it would have to be shut down for that.
They could probably cite Fox news claiming it.