It would be silly to expect a company to focus on SP when FPS players mostly desire good MP. As someone else said, most of my friends that play FPS don't even touch the single player campaigns (I myself didn't start CoD 4's until a few months ago).
As for someone's remark about RPGs, I don't think I agree. In terms of non-MMOs, Lost Odyssey, Tales of Vesperia, you mentioned Dragon Age, these are some great, recent RPGs (even if Tales has some MP, I doubt you could say they focused heavily on it) with great stories.
Also, plenty of MMOs bring in loads of cash, even if they aren't nearly as successful as WoW. Low Server Maintenance and post-development costs coupled with high subscription fees, and/or in-game item shops generate a lot of revenue.
MP is all the rage, it's more fun to play games with friends than to play alone (this may not apply to everyone, but most people feel that way, especially casual gamers). I think it's great that companies focus on that. Don't get me wrong, I like a good story/campaign as well, but I don't look to FPS for those. Rpgs, movies, books, etc. typically have better stories/characters than I've seen in shooters. But hey, that's just me.







