Yes, I'm sure the game with the most copies sold(unless you count DMC3 + SE) killed the franchise.
Sales dont matter. Fans got conned and bought Devil May Cry 4 for the Hype. I'll explain this easily for you to understand. Devil May Cry 4 and Devil may Cry are like Final Fantasy 13 and 13-2. Get hyped and buy the one the next come out and over 60 percent of the people who bought the previous one back away.
Still playing The Mass Effect Trilogy for the forseeable future. I may be addicted.