Nailhead, meet hammer.
For thousands of years, much human work could be done just about as well by someone of well below average intelligence. Doesn’t take a particularly high IQ to be a galley slave or serf. In fact, intelligence was quite likely a hindrance to survival, as you’d probably more likely to “get above yourself” and be killed by someone above you in the social hierarchy. See the Jim Crow South.
The Industrial Revolution increasingly removed the demand for human muscle power, to the point where in advanced countries it is very nearly gone. As are the jobs that require only it.
The Cybernetic Revolution is in the process of doing the same. An IQ point falls out of the effective demand job market every year or two now.
New (and better) jobs are created, but most of those displaced are simply not intelligent enough to be retrained to perform them.
The world of the future will be immensely productive, which means that huge amounts of “stuff” will be produced with very low and decreasing human effort. Which means, by definition, more and more people will simply be redundant to the economy other than as consumers.
As its last great act of creative destruction the free market will destroy itself. It is by definition a mechanism for efficiently distributing scarce resource. When resources are no longer scarce, the market will disappear, at least over large areas of life.
I have no clue what will replace the market economy, but I worry it will be the all-powerful state.
It’s not just IQ, you can have a high IQ but if you are 50+ nobody is going to hire you in a number of fields. So what you do is to make your own job starting from scratch, and if you are successful you will make more work than one person can do :)
This is probably what results, paid for by those making those high-paying salaries:
Guaranteed minimum income (GMI) (also called minimum income) is a system[1] of social welfare provision that guarantees that all citizens or families have an income sufficient to live on, provided they meet certain conditions. Eligibility is typically determined by citizenship, a means test, and either availability for the labour market or a willingness to perform community services. The primary goal of a guaranteed minimum income is to reduce poverty. If citizenship is the only requirement, the system turns into a universal basic income.
https://en.wikipedia.org/wiki/Guaranteed_minimum_income