You don't think that page was chosen as an example because it should be a very inexpensive page to render? I read that as saying that the performance problem do

You don't think that page was chosen as an example because it should be a very inexpensive page to render? I read that as saying that the performance problem does affect all pages "even on THIS mostly static page." As for your skepticism of the graphs, take a look at the annotated R source they provided. I didn't do a deep dive on it or anything but it looked reasonable to me.