@sqiddster - in terms of file I/O, there are some HTML5 technologies that can effectively do that but sandboxed to a domain. Basically there are several features you'd think would be specific to node-webkit, but actually can be interoperated with a web browser in a useful way - and that makes porting much, much easier. Having platform specific plugins generally goes against the purpose of HTML5 being portable everywhere.
@True Valhalla - I think you missed the point of my post - it's more about where things are going, than where they are now.
@Konidias - running a game through a browser probably does need more resources, but often it doesn't matter. It doesn't matter for desktop games. One day it won't matter for mobile games. Also Apple are one of the strongest supporters of HTML5 on mobile; for a long time Safari has been the best mobile browser by miles. I think if they wanted to hold it back, they could have done a lot worse and still been better than everyone else. WebGL is technologically complex and has a few issues mainly around driver compliance, which could be a contributing factor to Apple's decision to hold off for now. We'll just have to wait and see though - I have a feeling Chrome for Android could put pressure on Apple to compete and match it for features, which might influence WebGL support.
@jayderyu - I think you're behind the times. Did I mention you can already enable WebGL on Chrome Beta for Android? I think this is good evidence they intend to have it enabled by default in the stable release. BB10 and Firefox OS will be shipping with WebGL-supporting browsers too. So WebGL is already here on mobile in some ways, and it's improving.