Hiring and training a new employee when the person you would expect to train a new employee just quit without notice isn't as cost-effective as you might think.

If you have a spate of employees leaving over such bad behavior a good owner might be asking questions about high turnover, where your standard owner could give a shit about turnover anyway. They'll hire meth addled freaks as long as they're dealing with people with zero self respect. It really doesn't work out too great in the long run.

...hiring an employee that won’t push back on anything.

Thats the problem. For every worker who demands the respect and dignity they deserve there's a thousand other workers that have already been beaten into submission. The hope is that those "beaten workers" remember they can "stand up for themselves" when they see others do it.