I am convinced that the only thing IQ tests really measure is how well you take IQ tests. When I was a kid, my mother had to do a 'Testing and Measurements' course for her Master's in Special Ed, and part of it was having to practice giving IQ tests to kids. Since she had me at hand, I got lots of practice taking them, and guess what-- the more I practiced, the better my IQ became. I was getting smarter by the day! What a surprise.
So, when the school counselor brought me in in 9th grade or so (because I was getting lousy grades while seeming to be reasonably bright... at least I had a smart mouth!) and gave me a "real" test, I scored in the top 1%... the school counselor's only "official genius". Why? It's not because I'm the smartest person she ever gave the test to-- it's because I was the only one who knew how the tests worked in advance, and had practiced taking them. The questions may have been different, but the types of questions were the same; I knew what the test-giver was looking for, and fed it to her.
IQ tests measure your test-taking ability, and not your intelligence (whatever "intelligence" means, anyway). The guy at the garage I used to use probably had a much lower IQ score than I, but was a heck of a lot better at understanding and fixing car engines. And in the end, which is more useful-- being skilled at test-taking, or car mechanics? There aren't a lot of jobs for test-takers, but a good auto mechanic can always get a job.
We choose the strangest things to measure a person's value. Why does one FIFA Football star or US Major League Baseball pitcher make more money than fifty garbagemen or cops or firefighters or teachers? If the pitcher doesn't play for a month, how are our lives affected? If the garbagemen don't collect any garbage, or if the police department or fire department is short fifty firefighters or cops for a month, or the district loses fifty teachers, how are our lives affected? To be honest, I'd rather my team lost some games than be neck-deep in garbage and rats, or have my house burn, or be robbed at gunpoint, or have my grandkids be illiterate.
People who can throw a fast really well are highly paid and honored. The people who really make a difference in our lives are paid as little as we can get away with, and ignored. Folks with "high IQs" can boast and join groups like MENSA, where they can pat each other on the back for being so brilliant... I'd rather honor people who were useful to society than those who were merely "brilliant", or that could throw a baseball really fast. Hmmph. Must be something wrong with me.