Bungie is a company with a lot of talent and resources, I'm sure they can get one of the developers on board to develop a universal app. Also, Bungie isn't looking to generate a profit from a companion app (there is no profit to be made), they're looking to broaden their fanbase as much as possible and engage the players into their game over the span of Destiny's lifecycle. So the question about marketshare and profit should be thrown out the window.