IQ tests like SAT scores are reliable indicators of various cognitive abilities, much like 40 yd dash times and vertical jump is used at NFL combines to select future pros. We all know pro football players that were not the fastest or the biggest, etc. BUT if you take the avg 40 time of the top 50 def backs in the NFL or body mass of the top 50 lineman, it clearly shows some standard.
It is easy with human beings to find some excpetions. BUT, if you look at MILLIONS of people and IQ, one will see that academic success and degrees that lead to various professions go hand in hand with IQ.
NOBODY with an IQ below 85 ever became a top level math or physics prof or obtained an MD from a top med school.