Right. Though I want to focus on a specific aspect of your hypothetical (which is essentially real):

If the manager hadn't stolen $100 from the cashier, there would have been a MUCH weaker incentive for the cashier to steal themselves.

This is the crux around which everything else turns: we are effectively post-scarcity, as far as production is concerned. As a society, we purposely create theft, and debt, and the associated desperation and crime, as a matter of policy. As a choice.

If you were eradicate wage theft, you would essentially eradicate the internal logic of street theft, in the vast majority of cases. We could just... not have theft. But by not prosecuting wage theft, we, as a society, have decided that we condone and even need theft.