> Or for that matter, rewriting your app for every phone platform.

Cordova, Qt/C++, Xamarin Mono, Unity, Cocos-2D-X, Titanium, ....

There are lots of alternatives to minimize duplicate native code. Plus it is not as if one doesn't need to write once, debug everywhere with HTML 5.

And how much of the apps written with such frameworks will feel remotely like a native app? How much of the frameworks you mention even support a reasonable amount of target platforms?

I don't disagree HTML5 has porting problems between devices & browsers. I'm just saying that native apps have more.

I can't speak for all of them but I use Xamarin at work, and it absolutely does translate to native look and feel for the app. Although once you get to the GUI layer, it's not much more than a thin C# wrapper for the native OS framework and you have to write a lot of platform specific code. But everything else is cross-platform. And you're coding in C# and not Objective-C (or Java), which is a more predictable and less verbose experience, at least for me, and I've made half a dozen apps using Objective-C.