if activision start charging a subscription fee, they can't charge for dlc like map packs and stuff which i think gives them more money. reason being with a subscription fee they would loose a lot of their fan base, atleast 60%. which mean a lot less people buying dlc.
if the whole industry started charging a subscription fee then they could charge for dlc BUT that would just lead people to playing a mmo. you can find an mmo for pretty much any genre (fps, racing, ect).
also the reason cod is so popular is because of friends. if they charge for online and loose a big part of their player base. there will be less people promoting how good the game is when they hang out with friends or have a party. also if your friend doesn't want to play "that" game because he/she doesn't want to pay a subscription fee or can afford it, how likely are you to pick it up instead of picking up a game you can both play?
