80% of people hate their jobs.
What would happen if they got paid more? They might save up and quit. This is why employers will exploit, (pay less than they can), every employee for as long as possible.
If an employer has someone stuck in the Zombie Loop and living paycheck to paycheck, then why would they ever willingly give that up? They have guaranteed profitable labor. All they have to do is kick back and watch their employees bring in the money.