While this can be true, this absolutely is not true for the majority of paycheck-to-paycheck people. You truly need to get your head out of your ass if you honestly believe this is what is causing people to be poor.
Yes, sometimes this is medical debt or other unavoidable things. But its also true that the consumtion rate is incredibly high and the savings rate is incredibly low, with US credit card industry making it easy to create huge debts.
So its simply a fact that a huge amount of people live in self imposed risky situations. Instead of an emergency fund, they think they can just open a new credit card.
So its of course not what is causing people to be poor, but what is does is that it makes many, many more people 'living on the edge' then there should be based on their actual incomes.