@Potato: WebGL is going to be available for regulard web views in the close future, because it's already available for iAds (which are nothing more than glorified UIWebView).
It's fun to notice that everybody liked to bash Flash, and realize now that it can do lot of things that are not possible without it for the moment
However, Apple knows that if they allow WebGL on regular WebView, everybody is going to use it, abuse it (heck, I can even envision some GPGPU with it using shaders), and it's going to give bad user experience, and drain the battery fast. And if there's something Apple value more than every other technical consideration for their smarphone, it's the "public perception". They prefer to cripple some functionnalities but have the public thinks "hey, it's cool and shiny".
And about the 30% cut, believe me, every time a coder is skipping the AppStore and putting is webapp on the net directly without Apple AppStore involvment, they are happy and gain money ! (if they could, they would shut the store and drive everybody on the web - the AppStore is subsidized by Apple to sell hardware. That's what Apple is : a hardware company).