I've been doing HTML5 app development (via phonegap) on iPhone and Android for some time now, and I agree with a lot of what you said. You can make a really smooth, native feeling app using HTML5, but there are lots of things that don't work well. On iphone, there are lots of problems with fixed positioned elements, and on Android there are issues with translate3d. Both platforms have problems with "tap" events. These are all things that are important if you want a "native feel" in your app. However, there are workarounds.

I also agree that needing 3 front-end teams for app development just doesn't make any sense, especially for a small company. Since you can get near native performance with HTML5, it seems well worth the compromises.

FYI, my app doesn't use any mobile js frameworks, just Backbone.js (and phonegap).