I would like to point out that some of the best games of all time, like Super Metroid, are single player experiences, and that game in particular rides on the feeling of loneliness for much of it's atmosphere. I think many current developers care so much about just making some extra $$ they don't even account for how multilayer might effect the atmosphere of their game. They just know it's a shiny new thing and it has to be crammed in there.
Quite possibly the most hilarious and ironic thing about all this is that most multilayer games have the shortest longevity. Servers get shut down, the next iteration of halo/CoD come out and the previous one is forgotten and swept under the rug. Oh sure, you can still play Halo 2 and the original CoD games, but... not really. It's not like 'Shadow of The Colossus', which will sit on a pedestal until the end of time. Sony might not even exist as a game company 40 years from now and this game will still be there. You won't need any Sony servers or other people to play it with to get the best and fullest experience it has to offer.
I swear, between turning everything multilayer and trying for an all digital future, the game industry is burning their candle at both ends. It's staggering how naive they must think we are. But part of me is kind of glad that in 20-30 years almost every game coming out now will be unplayable. It will force people to go back and play the classics lol