Playing this game isn't mandatory either. If you don't like single player games, and are so hell bent on playing multiplayer games, then why in the hell did you buy this one?
Multiplayer has been asked for since Morrowind, perhaps earlier, but I didn't have internet when Daggerfall was released. How many gamesas releases have come out since that game? Multiplayer has been asked for for every single one of them.
This all ignores the fact that the game's engine would have to be rewritten from scratch to support this. The game is built with one avatar running around interacting with things, hell, cells shut down when the avatar leaves. You want to add multiple avatars, with the need to constantly update the clients of every avatar with the actions of every other avatar? The engine would literally crap itself.
This is known, but with every release of a Fallout or Elder Scrolls game, the whining for something the game isn't, or was ever meant to be never ceases.