That it's now accepted to pay $60 for a service instead of a product in gaming. A service they can shut down whenever they want (e.g. when the customer refuses to be ripped off by the DLC anymore). The cities created by the players could (or probably will) be lost. For some games like MMOs this is normal. For simulation games it was not.
There's a few for you, all by EA, one of which after only 15 months - except in those cases the single player was at least still playable. Unlike SimCity.