That's completely untrue. It is immediately noticeable because of the lack of responsiveness, smoothness of transitions, and ugly layouts. Like I said, you can put together a bunch of hacks to try and imitate it, but you end up with something clunky and unprofessional. This wasn't as big a deal 10 years ago, but interface expectations on these devices (especially the tablets) are very high. Quality design is expected by a lot more customers in the hardware AND software. Interfacing with touch gestures needs to be instant and seamless.
Did you even look at the "Ali Quotes" app in the story? It's terrible. I've poked around the jQueryMobile already on my iPhone, the whole thing is, in a word, slow. Yes, I know it's new. It will be better in six months... after thousands of coding hours will be spent concocting ludicrous javascript and CSS hacks to duplicate something that's been done perfectly well on native client platforms for 3 years. It's a terrible waste of effort.
> There are also some heavy downsides in Xcode/Obj-C development, such as hunting down memory leaks and crashes
True, these are problems that have existed forever, and better dev tools help alleviate them. But don't forget these same problems are prevalent all over web apps too. Flash memory leaks are everywhere. Javascript suddenly consumes 100% of your CPU. Same problems, but no one care about fixing them because its just a webpage, just reload it. Well OK, but that's why even after 10 years people don't trust webapps.