Genuinely the biggest issue with trying to play the older CODs with friends is them being overpriced *before* you even start factoring the DLCs in.

BO4 is locked to battle.net and Strike Team was locked to IOS. (So I never got to play the latter at all and I only got to play BO4 after it was mostly dead.)

Same goes for the console exclusives.

Granted I'm sure the "real" reason this happened is probably a marketing stunt for MW4 or a mistake.