Atheist. said:
Not trying to argue most of your points, but there appears to be a single player here.
"Will there be a single-player component in addition to multiplayer?"
"Yes. In addition to battling the hordes of the Burning Hells cooperatively with friends over Battle.net, players will be able to adventure through the world of Diablo III solo. More details on both the single-player and multiplayer experience will be revealed at a later date."
I've found this quote on numerous websites.
I'm fairly confident there is single player, you just need an internet connection to use it. Plus, there are always mods to fix it, if there seriously isn't the option at launch.
Although considering the quality of Blizzard games, can you blame them for wanting more money than the 60$ (Or whatever it is in your region) per game? At least they aren't charging everyone more money. They have seem to be getting greedy recently, but I think that started when they merged with Activision.