He means the network effects (in this case, the App stores) create a situation of huge dominance of one player over the others. Apple was headed to that position, but what happened was a whole new market of low-end smartphones opened up, witch Android ate up. So you can think of it as a winner-takes-all in the high end and another in the low. Of course competition should and will happen (I have hopes on FirefoxOS), but in these markets the new player usually storms in with domino network effects and pulls dominance to his side. Technology is either you're rocketing up or dying a painful death, it's rarely a healthy sustained competition.