I've said before (The W) that I don't think online gaming is all that important to the current crop of console's sales. Here (gamesarefun.com) is an editorial that agrees with me. I'll concede that some of the points sound like whiny complaining (its too hard/expensive to set up a home network), but they are all legitimate reasons why its only the hardcore gamers pining over any lack of online content, and not the gaming masses.
Microsoft's problem, it seems is that they're operating from a position of weakness. They desperately need a knockout, system-selling game, but with lousy first party development, it's not going to happen.