I classed that in with doing GPU computations in JS; it may work in a carefully selected browser and GPU combo today, but it's going to be a while before it's out there.
And even if your JS is running at native speeds, it doesn't solve the bandwidth problem, which is nowadays arguably the distinguishing characteristic of a supercomputer, since the compute nodes of a supercomputer are hardly any faster than a commodity desktop anymore. (Some, yes, sure, but nowhere near the multiples there used to be.)
Great essay. But I'm surprised PG didn't mention Pretotyping. Here's the Pretotyping PDF that hammers the point: make sure you are building the right IT before you actually build IT:
