Since 1993 SAT no longer stands for 'scholastic aptitude test'. It had its roots as a sort of IQ proxy but that has fallen out of favor because it doesn't reflect the full purpose of schooling (e.g. advancement from given means, value-add of schooling for a given student) nor range of things that cause students to achieve (e.g. hard work, conscientiousness, etc).

One could make a test called 'big brain test' and sell it to schools to say it measures big brains, and it might be only somewhat correlated but still get widespread adoption because it fulfills a need schools have to have some sort of quantitative sorting of students, but it still wouldn't necessarily be a measure of big brains. This is sort of what the history of the SAT is.