I'm glad the article doesn't try to extrapolate that HTML5 has won mobile. I doubt that developers whom attended two hackathons are unlikely to be representative of the state of mobile development.

Also, I'm unsurprised that HTML5 developers are well-represented at hackathons, IMO in the context of a hackathon, i.e. building something from scratch in a highly constrained time frame, one can achieve a lot more in HTML/CSS/JS than in a native app. This might be down to my greater experience with web technologies than native mobile development, but I believe the tooling for web technologies are better suited to rapid development, e.g. I can rapidly build layouts with tools like CSSEdit2 and see how my changes affect the document in a WebKit view, in realtime. You also don't have to run a build process to see results, feedback is in general, instantaneous.