maybe they want to start to sell more pokeballs? In the end most games makes their money off a small percentage of power users (aka heavy addicts) who are ready to shell out money for in game purchases - a game does not need a massive following, they need to hook a small circle of friends (015% according to [1]) who are ready to pay.

[1] http://venturebeat.com/2014/02/26/only-0-15-of-mobile-gamers...