Yes, and that is why over time this is becoming more important. To put out some arbitrary numbers, you can use a shovel with an IQ of 70, you can operate a backhoe with an IQ of 90, you can engineer the backhoe with an IQ of 120. Manual shoveling disappeared as an occupation 50 years ago apart from niches, driving as a profession might disappear in the next 15 -- and it does matter whether the people made unemployed by technology can be upskilled to be repairmen/engineers/programmers. If IQ is >50% genetic, they can't and you have to figure out how to deal with 10-20% of the population being permanently unemployed or employed in extremely-low-skilled jobs.
I think this requires rephrasing: The fact you _can_ engineer the backhoe, means you have a higher then average IQ. The fact you have the engineering degree and education required gives you a higher likelyhood of having an above average IQ.
I’m sure you _can_ engineer a backhoe with an IQ of 90. But it is going to be harder for you to get the degree and education required. Whether it is harder because of some lack of some mental capabilities or because the whole education system is stacked against you because of your socio-economic status (which is predicted to be low given a lower then average IQ) is debatable.
this is ... breathtakingly naive
However if you go the same number of standard deviations up (~5.333) and get to 180 you don’t see any super human mental capabilities. In fact there is nothing really that distinguishes a 180 IQ from the average 100 IQ (except socio-economic factors like education, well paying job, rich educated parents, white or east asian heretige, etc.; and you didn’t need the IQ to tell you that).
In short. IQ is never useful when you measure above the average, and only the test generating the IQ are useful when you get several standard deviations below the average.
Among the illegal drug trade and other criminal activities IQ strongly correlates with success and positions even well past 100 IQ.
The US military found increased IQ over 100 to strongly correlate with lower training costs. So initially flat out IQ tests and now an IQ proxy is still used to screen people before they can take jobs requiring significant training.
An IQ of 100 is defined to be the mean intelligence. It is a magic number (albeit not a magic number representing competence). Usually an IQ of 80-90 (around one standard deviation below the average) give you general competence, lower then that and you probably have some mental disabilities (unless the test is badly standardized; which has happened more often then it should have).
IQs above average correlate with loads of desirable things, individuals with higher then average IQ are generally more well spoken, they have higher income, they are quicker to respond to questions, they know more jokes, they are probably more handsome as well (I know; citation needed). These traits are as well desired (if not more) in the criminal world as anywhere else. But this is precisely the problem with considering high IQs. If your measurement is predicting everything, it usually means you are measuring nothing.
> If your measurement is predicting everything, it usually means you are measuring nothing.
The goal of IQ was to predict everything as it's a one dimensional scale. You can always find a better test for any given quality, and frankly should. However, that does not somehow invalidate it's wide ranging utility.
If not: Using IQ for anything else is, at best, quite useless, and at worst, severely problematic as you found out when you heard about scientific racism (such as the eugenics movement).
For fair disclosure, there was a study which showed that as IQ decreased, the span of time for a perfect IQ score prep increased almost infinitely, as the low IQ kids forgot the material they already learned. Maybe I will look for it later, would be very relevant here.
Though presumably that's just gaming a test and has zero impact on IQ as measured by unrelated tests. However as this makes the tests less accurate it's discouraged.