That’s the hilarious(ly depressing) thing about buying a digital movie, for example, to me.

If you rent it, you get it for a certain amount of time.

If you ‘buy’ it, you also rent it, just for an undisclosed amount of time that they may or may not retroactively take away from you at any point with no warning or compensation.

Your use of the Platform is licensed, not sold, to you, and you hereby acknowledge that no title or ownership with respect to the Platform or the Games is being transferred or assigned and this Agreement should not be construed as a sale of any rights.

From the Blizz terms.

WoW has always revolved around having a server handle everything and your client is just the textures/models viewer where you tell the server what to do, I have been fine with this. But I do agree, it should say something else on the button. Other games that are not MMO shouldn't be a "license" to play. If you buy it, you can play it whenever and wherever. Features that are not multiplayer should work regardless. Some things just shouldn't be tied to a server. I really despise modern gaming because of this.

Anecdotal experience: Gran Turismo Sport recently lost its servers. When they went down, the Mileage Exchange shop went with it. This means all the cosmetics for cars. and a few unique cars, are now unobtainable for future players. PD could have patched the shop to be a complete list of everything and you buy it with the plethora of points you will collect in the future as you race. But no, they didn't.