You sacrifice the best things about a web OS if you wrap it in a traditional OS UI.
Letting "the web optimize" your dialer, though, is perhaps the most dangerous idea I've heard in a while. Core applications under no circumstances should be optimized by the web because that's how you get malware masquerading as those core applications. No bueno.
I think the implication is that if FirefoxOS had focused on making it not awful, they would have done really well.
It'd be awesome to have a phone for which app development is all done in HTML / CSS / JS while still remaining fast and efficient.
Apple - you don't need native apps you can build great web apps. Developers and users rebel, a native SDK is introduced 9 months later.
Blackberry - you can build apps using Adobe based web technology. You get the picture...
Instead of web apps, Google stuck the world with a sub optimal Java implementation that they spent years trying to optimize.
Today they see Google Dominating because of Pure marketing, so they want to chase that dragon... They are killing everything Mozilla stood for in the process.