More ammunition came a short time ago from the Financial Times, who released a rich iPad web app that is every bit as articulate as a native app. The FT's designers discuss that decision here.
The excellent FT iPad web app suggests that native app UX only surpasses web app UX because typical web apps don't put in the effort.
There's very little I find in native mobile apps that I could not do as well in a web app (HTML5 plus concessions to using platform specific CSS and JS calls). In some ways, the UX already is better in a web app. I almost always find that native apps lack some critical functionality that the web app has. And the web app has seamless hyperlinkability, in and out.