No, I don't play enough multiplayer in general enough to warrant such a purchase. It isn't a "games need a single campaign" idea, because I could truly care less. For me it is simple money managing. I don't have the time or the effort to put into said games in contrast to the amount of joy I'd receive, so I don't buy them.
I think of it like a genre, and it just happens to be a genre I don't enjoy very much.
That being said however, anything half assed usually isn't worth it. Why waste development time and money on something that isn't a main selling point. Erase a campaign story mode and include an option to play vs. some bots like in the old days.