The system is set up such that if you lose your job you lose your health insurance, for you and your children.
And if you miss a paycheck you’re toast. Probable eviction notice in the future. Paycheck to paycheck living is real, even more so in the post 2020 world.
I'm guilty of it too but most people living paycheck to paycheck could avoid it. Bottom thirdish is definitely stuck in the poverty trap but most could cut their expenses if they tried.