CoD: You looked at the past 3 years, which all had games in the series with very slight changes.
Sonic: You looked at the 10 years BEFORE those years, which at least had significant changes.
No need to look at Sonic's recent history, right? Just keep thinking about the middle-aged glitches, werehogs, and bad controls. There wasn't even a 3D Sonic game in 2012, because the developers probably figured, "Eh, we did our little celebration of the past 20 years and made up for it with VASTLY IMPROVED LEVEL DESIGN for the AWESOME levels from our most popular games back then. Let's give it a rest."
Seriously, go play Sonic Generations (or Colors, its prequel on the Wii) and see what I mean.