What he describes as the "most important reason" is also the big mistake here. If using certain libraries or cross-platform development tools truly did result in worse apps, then the market would take care of that. He also doesn't seem to understand that such tools do not all totally hide the underlying APIs. They fall along a continuum in that respect. And in trying to ban extreme cases like Flash, Apple has also ba…
There are many people (young people) who don't know anything about design or hacking, but they know enough to make an app in Flash--sort of. And when people buy those apps that look, feel and work like crap, they'll think iPhone itself is crap. Sure, they might pay for more expensive apps (those that are still in business), but once you get in the habit of paying little, it's hard to start paying a lot. I still buy cheap motherboards and curse myself later. And, once you get in the habit of getting crap, it's hard to expect anything more for your money. At this point, Apple has no edge over Android. Et cetera.
I can see a strong case for why it's evil, but to show that it's stupid would require thorough understanding of what a clueless, fickle public would do. Maybe the business morlocks at Apple are better at that than we are, and maybe we're better for it.