First, jashkenas isn't held up by standards committees -- he's able to experiment with cool new client-side web tech on whatever schedule he wants. And building on this, even more new stuff is happening, like Tim Disney's contracts.coffee .
Second, your ability to ship the coolest new client-side technology isn't being held up by TC39, or by the HTMLWG -- nothing we or they could do would make MS ship IE 9 for XP (or make people upgrade from Debian Stable :).
Third, the reason that design takes a while is because it's hard. I'm really glad that Dave Herman and I haven't iterated the ES6 module design in shipping versions of a browser -- that's not the right thing for anyone.
Finally, you mention Scheme. If you want to see a truly disastrous example of language progress held up by politics, check out the last 5 years of Scheme standardization.
I guess I was wrong when I said every browser innovation. I also, more or less, agree with your other points - my goal wasn't to bash HTMLWG but to point out that the standardization of a lower level api will help us skip some of the other parts of the standards process by allowing us to do things like compile an sql library directly. Design is indeed hard, but with people free to implement different alternatives, it can happen in a distributed way with more possibilities explored even in production systems. Of course, something as basic as a module system should definitely have a standard. Which would also lead me to agree with your comment on scheme standardization while noting that some of the experiments with first class environments and f-expressions seem to be a genuine exploration a new part of the design space and not a gratuitous incompatibility, but maybe the standardization process should ignore them for the time being.
Quick comment: lower-level APIs can be harder to standardize than higher-level ones, depending on the diameter of the API-set and the implementation dependencies. Running native binaries requires a new compiler and a bunch of runtime API support (Pepper).
OTOH adding typed arrays or binary data to JS is narrowly targeted and pays off for higher-level API builders. And the typed arrays and binary data specs are being standardized.