Quote Originally Posted by Bolivar View Post
I think that's a superficial belief that very few people honestly follow through on. I never touch the multiplayer in series like this that shoehorn it in (like Dead Space, Bioshock, Tomb Raider, The Last of Us) and I suspect most do not either. Nor have I ever felt like alternate endings or characters make as big a difference as people pretend they do.
You're mistaking your personal preference for the preferences of the gaming public, especially in regards to multiplayer. This is fine when you're considering the value you personally place on these products, but not entirely relevant if we're looking at wider consumer behaviour as your post implies.

Is it mandatory for a game to have multiplayer to be a good game? No, of course not. Does it increase its lifespan and therefore value as a product? Assuming you even try it just the once, yes. If you don't have the slightest interest in multiplayer, no.