Pay check to pay check can mean literally that. Money comes in, money goes out. There is no buffer. UDP not TCP life :D.
This hypothesis presumes that loans are priced exclusively based on cost.
However, all products and services are priced based on willingness to pay, and profit is the delta between cost of delivering it and what customers are willing to pay.
Price gouging runs rampant on credit cards because they are designed to gouge their users. The credit card adoption and payment customer experiences are extremely smooth and free from any resistance to the point where you can pretty much find yourself with a new credit card in your pocket without knowing how. However, avoiding charges and interest payments is extremely hard by design, specially when compared with debit cards. Customers cannot escape these charges, and with low income customers they syphon a relatively large portion of the little disposable income they have.
Rates are relative, looser money absolutely translates to lower rates, even for poor people. Claiming otherwise is (social) science denial.
> modern poor people generally have zero assets.
Poor and lower class people are often deeply in debt. Many poor people will even have homes with very large mortgages outstanding, and without a route to paying it down. The median black person in Boston, for instance, (not to conflate race and poverty, it is just an illustrative statistic that comes to mind) has $8 to their name. That does not mean they literally only have $8 in a wallet somewhere, but it does mean half of those people are underwater in debt. This is before you even start looking at mortgages. I'm assuming that is not unique to Boston.
That is actually very analogous to the situation we are finding ourselves in. Tighter policy would increase the real value of the payments that poor people have to make on their homes, etc.