@Jeff; yes, but the concept of Diplomacy does involve alliances.
I guess this is all coming down to the fact that, in a way, I'm less cynical that most of you. (Although in other ways I'm probably among the most cynical.) I like to think that the world's problems can be solved by working together, and like when the game reflects that. But then again, that's just psychological analysis.
Alternate theory: it's not that I'm less cynical, it's that I have an urge to be a dictator--a mostly-benign dictator, but a dictator nonetheless--and thus want it to be more realistic; as in, where multilateral solutions are best. Again, that's just a psychological theory as well.
My opinion is how it is on the matter, regardless of how it was formed. I respect other people's opinions, but I don't see that my opinion is likely to change.