This feels like a pretty strong over-application of the computational metaphor, my friend.
If we extend the metaphor, there are 4004s and there are i7s. You need a lot of 4004s to equal the output of one i7. That many 4004s use a lot more watts than the one i7, and at some point the value isn't there.
IQ (g) is normally distributed.
The only hope here is that there is some extrinsic element, similar to nutrition, but as yet undiscovered, that will improve human IQ for those on the left-hand side of the curve in a real way. Otherwise, no, not everyone can contribute in the same way.
Is this a joke? It sounds like something so detached from the reality of humanity that it's something only an engineer or computer scientist would say. An unemployed human isn't a 'waste' of anything; the fact that the human does not need to be employed but is still suffering at the hands of capitalism is horrible.
Yes. The aptitude of higher abstract thinking varies greatly among different people and groups.
If you are really curious, check out the IQ test about pulling info from a sports column.
After that, your question becomes similar to asking why every short person can't be taught/trained to do well on a professional basketball team.
The number of active NBA players is in the hundreds and their careers are short. Education is a very effective weapon against multi generational poverty and the focus of international aid organizations for a reason. Someone from an impoverished background is much more likely to live a better life with more education than someone without.