This worked amazingly well for querySelector (vs jQuery's sizzle and friends at the time), but IIRC, JIT is so good now that there are APIs written in JS _because it's faster to do so than to use AOT_. I recall reading somewhere that the cost of jumping between JS and C++ land was a source of slowdowns with the DOM API, so there's that too.

But overall, I agree with the idea of incorporating the ideas that are working into the platform. There have been various discussion over the years about how virtual dom could work as a native browser API, but unfortunately, the needle hasn't moved there at all.