That is indeed Parrot's vision for the distant future, but even I as a Perl 6 developer and advocate think that it's far off in the future.
Browsers embed highly specialized and optimized javascript JIT compilers, and a general-purpose dynamic VM like parrot can't really hope to compete in terms of speed any time soon. And since speed is a major concern for browsers, we can't really expect to see wide spread adoption of parrot on the browser level until the performance issues have been sorted out.
