looking at the various sales estimates and reports, it seems
WWII did infact "bring the franchise back" as it's above 21 million copies as of January,
Blops III did ~24-25 millionish if you want to count the gimped 360/PS3 versions that only had MP but still sold ~2 million,
Infinite Warfare then only did like 14 million or so,
Ghosts was the last one to crack 25 million easily, looks like ~27-28 million...the peaks were
Blops and
MW3 which both did 30 million
so i guess people just don't like space?
as an aside, it looks like
Call of Duty 2, the undisputed peak of the franchise*, did a whopping 2 million copies, the 360 version was outsold by at least ten PSP titles in 2005 and
Nintendogs sold at least 9 times as many copies, oh we were so innocent back then
*