No, it's not. But you can have an okay life, assuming you don't have a family.
Why shouldn't someone working full-time be able to have a family?
The same reasons why teenagers probably shouldn't?
What? A teenager isn't expected to be self-sufficient.
Which is why minimum wage jobs are ideal for them. Unfortunately, there aren't enough jobs available farther up the chain. So older people with families are taking the low wage jobs.