If you're making $100k a year, living in a nice 4 bedroom house, driving late model cars, and not saving, that is a relatively easy fix.
If you're making $10 an hour working retail, there just isn't enough money to pay for cost of living and any kind of substantial savings.
People in this situation (who make up a huge chunk of America), are one expensive car repair away from disaster and debt collectors.
Now, obviously you don't want to get into this situation in the first place, if you can help it. But if a person is, then they are not simply doomed as you're saying.
We should not excuse exploitation of people living paycheck-to-paycheck simply on the basis that they're bound to get fucked over eventually so it doesn't matter when or how it happens.