As games have grown as a medium it has essentially turned more into a business focused development cycle rather than purely out of interest in creating video games as it used to be. Certain publishers have become massive powerhouses and control a large amount of the industry, or at least in the sales department. But for these publishers to please investors, etc. they must gain as much profit as possible. Because of this the big publishers have begun to notice that they can release more games in franchises, more frequently and still make huge profit since fans of these games want to play them so badly. Once this reaches a certain amount of games, or the releases become too frequent we start labelling them as ‘milking’ the franchise. Personally I think that the ‘milking’ of certain franchises has not been entirely beneficial, or otherwise I feel like certain franchises are not living up to their full potential.