Will JavaScript get fast enough?

At the last Google I/O (2011) the V8 team mentioned they've done all the major optimizations they could and the focus should now be on DOM/CSS/etc to get more performance. I'm guessing that's why they have the Dart effort, to change the language to build a faster VM on top but maintain legacy support.

So from this point, how much faster can current JS get? Does Mozilla's JIT/VM approach have a higher performance potential than V8?

I think the major problem is the improvement speed of the web. Mobile OSs are rapidly advancing in features, speed and users, while web and its minions are complacent. They point to the old victory of open Web over closed AOL/Prodigy and pretend the situation is the same now - always bet on JS.

JS and the open web have a lot of political clout but I wouldn't bet on the technology improving rapidly when the decision making process is mired in politics. The open web can remain a dominant platform for a decade even if its technology stagnates. It's not much of a bet.

A major feature of Native Client is it allows a part of the web stack to be removed from the political circus. Look at CoffeeScript's popularity and usefulness. What if the creator had to ask Google/MS/Mozilla for their point of view, it would never happen. A piece of the stack, JavaScript, was flexible enough to avoid the open argument circus and be tested in production. What if it was more flexible?

That's what Native Client allows, to agree only on parts where we can't handle disagreement technologically and have more experimentation with the rest.