I happen to have the opposite view, specially with Blend and component libraries into the mix.

CSS had to get WPF grid design in order to not be a poor table sibling in what concerns layouts.

While WPF is backed by DirectX, CSS requires playing with Z order, so that some browsers might eventually put the rendering into the GPU, but one needs to take care because space is limited.

While I can render anything down to pixel level control, if I wish to do so, I am still waiting for Houdini and worlets to actually become available.

And the whole template language with events and theming for low level customisation of control behaviours? Nowhere to be seen.