Honestly? I don't blame Activision/Treyarch at all here.
Obligatory campaigns are stupid. I wish other games would take note *cough*Battlefield*cough*. I'd much rather have a extremely quality mutliplayer experience than a boring-ass, by-the-numbers campaign and middling multiplayer. Put those resources toward a full multiplayer game instead.
Last gen people complained about "tacked-on multiplayer." Well, tacked-on single-player exists too.
Now to be fair, I haven't played a Call of Duty campaign in years -- the last one being Black Ops, so I can't speak for their quality anymore. And I'm not sure how many people still care for their campaigns, so maybe I'm wrong here in COD's case, but my overall point still stands.
And I'll never understand the people who adamantly think multiplayer games should not be full price.
There'll always be Nintendo and Sony to save us.
This is true. Plus indies as well. I know a lot of people write off indie devs, but they have been massively improving in terms of scope. You can easily find quality single-player indie experiences that are pretty polished these days.
As far as Sony and Nintendo go, I think they're both safe bets for getting SP games for years to come. Sony has seen unprecedented success with their franchises since focusing on single-player, and Nintendo has kept their massive success as well.
I'm way out of the loop, but the only single player campaign I EVER heard anyone universally say they enjoyed was COD4: Modern Warfare. And mostly for the nuke scene.
COD1 and 2?
wait, are you talking strictly about COD games or campaigns overall?