500k ops is ridiculously slow for accessing the DOM on any modern hardware. It sounds fast when aren’t comparing it to anything. Compare that to a similar approach that makes use of the standard DOM methods and no selectors. The only thing querySelectors do faster is allow accessing elements by attribute.

The reason I refuse to post numbers myself is because:

1. I provided a tool where people can run any manner of discovery for their own numbers and see performance differences in various approaches.

2. People, when presented with a valid comparison will irrationally ignore results that challenge their opinion.

EDIT:

I looked closer at the measureit experiments and it seems there is some sort of bias. If you run the same experiment using an element already present in the page the results are the same for querySelector but 50% greater for the getElementById approach. Other perf tools I have tried did not display this kind of bias and they also reported substantially higher numbers for all user agents, most especially for desktop Firefox.