>> Either way the optimal societal goal is that if the worker works a bit harder they should earn 100% of the profit from the extra work That doesn't seem to h

>> Either way the optimal societal goal is that if the worker works a bit harder they should earn 100% of the profit from the extra work That doesn't seem to have really ever been true for a lot of people. It's very rare for workers to be paid in proportion to the amount of profit they produce for a company. Salaries are almost always determined by the labor market and the average wage for the role. Wage labor, which most of these ISAs seem designed to promote, seems to be fundamentally different from the kind of sharecropping relationship you describe. I'm not saying ISAs are good either, but that this doesn't seem to be true for many, if not most, workers today.