Apple claim 300,000 registered developers. One wonders what would be a "critical mass of development".
One also wonders what would constitute "maturity" with respect to OS X. Would that, perhaps, have to do with the broad range and flexibility of the APIs one can use to accomplish what one wants from the development point of view? Has anyone actually tried to use Quartz for text imaging?
I find your article wanting for lack of specificity. And, if you really wanted to be insulting, the correct term would be "Mr. Economist."