I get what you're saying, and I agree that's how it feels but that doesn't necessarily mean that's how it is.
I guarantee you there are companies in the US right now paying their full-time employees who work 40+ hours less than they pay consultants who are also writing code who are working 30, 20, even 10 hours a week or less. That doesn't necessarily mean that they're taking advantage of their employees (though they may well be). Everyone agreed to do the thing they're doing knowing exactly what the terms were.
If I agree to do a job for $X that is otherwise "not exploitation" by whatever metric we choose to use, it doesn't suddenly become exploitation if I could have gotten 2X or 3X to do the same job.
I guarantee you there are companies in the US right now paying their full-time employees who work 40+ hours less than they pay consultants who are also writing code who are working 30, 20, even 10 hours a week or less. That doesn't necessarily mean that they're taking advantage of their employees (though they may well be). Everyone agreed to do the thing they're doing knowing exactly what the terms were.
If I agree to do a job for $X that is otherwise "not exploitation" by whatever metric we choose to use, it doesn't suddenly become exploitation if I could have gotten 2X or 3X to do the same job.