Should I even bother on what's the source of this claim?
> Can You Ever Be Too Smart for Your Own Good? Comparing Linear and Nonlinear Effects of Cognitive Ability on Life Outcomes > Despite a long-standing expert consensus about the importance of cognitive ability for life outcomes, contrary views continue to proliferate in scholarly and popular literature. This divergence of beliefs presents an obstacle for evidence- based policymaking and decision-making in a variety of settings. One commonly held idea is that greater cognitive ability does not matter or is actually harmful beyond a certain point (sometimes stated as > 100 or 120 IQ points). We empirically tested these notions using data from four longitudinal, representative cohort studies comprising 48,558 participants in the United States and United Kingdom from 1957 to the present. We found that ability measured in youth has a positive association with most occupational, educational, health, and social outcomes later in life. Most effects were characterized by a moderate to strong linear trend or a practically null effect (mean R2 range = .002–.256). Nearly all nonlinear effects were practically insignificant in magnitude (mean incremental R2 = .001) or were not replicated across cohorts or survey waves. We found no support for any downside to higher ability and no evidence for a threshold beyond which greater scores cease to be beneficial. Thus, greater cognitive ability is generally advantageous—and virtually never detrimental. https://www.gwern.net/docs/iq/2021-brown.pdf
It is most explanatory at the low end; Cognitively Challenged. Elsewhere it has a correlation it is just not as significant, which is not in conflict with your link.
If you tested all the Children in the US you aren't going to be able to accurately rule out 84% of them from professional careers by IQ.
I look at it like this, for creative, intellectually demanding work IQ is a necessary but perhaps insufficient condition. You need to be smart to achieve success cause you are competing with other people, so smarter people will have an edge. Google is not hiring people with 90-110 iqs. So having a high IQ is needed to at least be sufficiently proficient in coding, to be considered for a good paying job, but not guarantee you will be hired, but being smart sure helps.