It's not cynicism I feel, it's dissatisfaction. I /want/ to use the web for powerful things, but the limitations of javascript make many of those things impractical. Hence my ambivalence towards "x in javascript"
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We have long had trouble agreeing on a standard for web-based native code. But that doesn't mean that it's a senseless request. The exalted status of Javascript is merely a convenient local optimum.
Most of the tech demo's we're seeing coming out of the JS crowd are from people who have only just started using the WebGL API (which is still experimental). I'm extremely excited to see the things that experienced OpenGL developers will be able to do as the API becomes more mainstream.