Right. If only select people could run the backhoe because of training, but anyone could shovel, then it would make sense that part of the productivity enhancements comes from the employee themselves. But let's just say the backhoe didn't require any special training. Should the worker capture some of the performance improvements that were derived purely from the business investing in productivity enhancements?
You write it at the end "improvements that were derived purely from the business investing in productivity enhancements".
Don't forget investment involves risk.
If you buy a backhoe, you might not find customers and you are left with useless backhoe and money spent, you still have to pay the wages to your employees first. Employee is not participating in any of that risk.
