This isn't so. Most employment is at-will. This works fine, because lots of laws govern what employers may do to employees, and anyway slavery is illegal so any employee may leave at any time. 95% of any employment contract is various attempts to get around those legal protections for the employee.
This is an especially pernicious case of the normal Stockholm Syndrome we see whenever the special status of corporations is challenged. No firm is 100% robots yet. If we withdraw our consent, they have to raise wages and improve working conditions until we relent.
