I think you're right, but that number should be correlated with number of users running browsers with JS turned off, which I suspect is trivial and shrinking.

I think you're right, but that number should be correlated with number of users running browsers with JS turned off, which I suspect is trivial and shrinking. The biggest issue I've seen with virtual-DOM sites is SEO. Google's crawler started using JS a number of years ago, but there are others that don't.