It's more likely they'd lose their job if they consistently receive bad ratings, from several different customers. And they should.
Given how much it costs to bring on new employees it's more likely that one bad review results in a consultation, additional training, etc.
Customer satisfaction surveys can be a useful tool, but they're often applied as a blunt instrument on employees who have no control over the situation the customer is dissatisfied with. It's basically a lazy copout as opposed to actually fixing company policy. I tend to ignore them unless it's to give good feedback.
A more humane system would take the feedback and then interview the employee in question and their management to understand what the root problem is. But the management organizations that use these surveys are almost never humane. Plainly, they don't give a shit about any of their employees.
I picture myself being let go from my job, I begin to feel the stress of doing the first inkling of planning that would be needed to survive that, and I decide that I didn't have such a bad time that I feel like pressing that one-star button, so I just close the feedback page instead.
I wouldn't want people to rate me one-star, so I don't rate other people one-star.
Until we have UBI, or a functioning safety net that universally guarantees shelter and food, this is false.