Ski Safari and Jetpack Joyride were very successful games, but they inspired many, many very similar games, making it very tough to stand out. I’m very proud of both Gunner Runner and Dragon Season, but I don't think we ever really had the passion for this genre of games to make something truly great.
The game developers were inspired by games which had tons of clones which made it harder for their game to stand out, because of this the developers lost motivation and lacked passion for the game.