The problem with FTP games is they miss a huge segment of the market. I have spent thousands on games, but less than 20$ on free to play games because I dislike the gameplay compromises needed to support FTP. That said, the app store funnels things towards FTP games but a subscription based game-play is probably a better long term money maker.
MMO's transition to FTP but just because Everquest decided after 15 years including several that crossed the 50 million dollars in of subscription revenue mark and 18 paid expansions that the best way to milk the remaining value was FTP does not mean it's best to start there.
although their ISK<->subscription time market seems like a nice compromise- if you can grind, you can play for free. If you want to skip some grind, you can pay to get ahead. And no one feels like they're being fucked with by amoral Wharton grads.
