Yeah, seriously. COD Zombies probably rakes in millions... It's constantly on the "highest grossing" list. That's should be enough proof that people will buy CoD on iOS.
+1 People don't buy iOS games because they're fun. People buy games like Angry Birds and GTA: CW (stayed at number one spot for a month at $9.99) and Chaos Rings (stayed at number one spot for a month at $12.99) because they have popular developers/trademarks/titles. If you don't have visibility on the AppStore, you got nothing, no matter how good your game is. That's the truth. Activision would have more than enough visibility to sell millions of copies at a faster rate than Infinity Blade if they do release a full-fledged CoD game, even if the game was price at $19.99. Apple caters to larger developers in any case. They'll ensure that the game sold well.
