This is addressed in the linked article in great depth. I don't think the poor performance of WebOS means that approach is fundamentally doomed, especially sin

This is addressed in the linked article in great depth. I don't think the poor performance of WebOS means that approach is fundamentally doomed, especially since FirefoxOS was a few years later... a few years during a period of massive year-over-year increases in mobile computing power. Long story short: relative to Android, they were bypassing the whole Java layer. Gecko (which is pretty mature + optimized) was essentially running on bare metal. Lose some performance here, gain some performance there. They felt this would offer strong performance. Now, to be honest, I literally have no idea how this played out in reality. Never even touched a FirefoxOS device. But, theoretically, there's no reason why this approach can't be pretty fast. At some point your apps need to talk to a widget-drawing layer. If implemented well there's no reason why an HTML-based approach can't be pretty darn fast, or at least fast enough not to be the limiting factor in your phone's performance.