It isn’t claimed that IQ is a perfect or total predictor of success. But it is the most persistent associated factor that we have. The highest end measurements among children historically had the most statistical error. The tests has been refined over the decades and of course the exceptions don’t prove the rule.
While it served me well to have that ability, I found that perseverance, tact, and inquisitiveness along with this talent overcame an innate shyness. I was able to achieve but probably not to the standard the nun thought I would. So, my feeling is the test is a tool in a tool box, nothing more. It still comes down to the individual and their ethical and moral upbringing.