While I understand how you arrive at the conclusion that the iPhone made the game all about app counts, I can't see how that stands up to Android coming along and ending up with a way larger selection. Even though it started as the biggest, Apple has kept a threshold in place that keeps out a lot of the crap. Not all, for sure, but you'd never get away with releasing something with the Facebook logo (or a poor approximation).

The fact that Microsoft took the bait of buying into the size of the store rather than going for a curatorial approach is their own doing. Laying blame on anyone but their own decision makers for the quality of their app store doesn't make any sense.