No test measures intelligence. A test only measures you relative to the persons that wrote the test. – loosely quoting Asimov.
2007 is ancient history now. It is an interesting graph that one might correlate with a lack of meritocratic structure in society, but I’m on the low end cause I say this without looking up and reading the study. Pretty pictures evoke emotional blabbering bias and all that.
Denying intellectual disparities denies the vulnerability of people with special needs, not to mention average folks who are constantly being deceived, swindled, manipulated, propagandized, and parasitized by the rich and powerful.