> What's the point of having these massive javascript virtual machines & webgl systems in our browsers?

Because the safety model of JavaScript has been sound for the past few years.

> How does having a separate implementation of a specification help us build a safer, more open web?

What seperate implementation of what specification? If you're referring to asm.js, asm.js is just JavaScript, any browser can run it. The "specification" is a gift to other engine implementers to super charge evaluation of compliant code.

> Is this supporting an open web?

http://asmjs.org/spec/latest/ http://code.google.com/p/v8/issues/detail?id=2599