[bgarbiak]

Well, one coud argue that developing one web app for a selected browsers is faster than developing a few native apps, each for different OS. Especially when you consider the fact that on mobile devices Webkit is a de facto standard and that issues like Android fragmentation doesn't make developing native apps any easier.

In my opinion, the real issues about web apps are: performance, lack of the Device API and a lack of matured tools. Solving first two is, luckily, a question of "when", not "if". The latest phones are already fast enough to handle even the heaviest jQuery monsters; LTE and 4G are getting traction and Device API is a work in progress (eventually, there's a PhoneGap). Lack of tools is harder to solve though. JavaScript grew big lately, yet in this field it's still very far from being mature. If you are doing anything non-standard in JS (like Backbone.js classes) the best you can get from IDEs, etc. is syntax highlighting. Hopefully, with more and more big players (like Adobe) hopping onto HTML5 bandwagon things in this matter will soon improve too.