Not sure if you're aware; but data has shown that being poor negatively affects your ability to plan finances in the long term. Because money is so scarce and it money seems to disappear quickly, it incentivizes the brain into spending money the moment you receive it.

I believe researchers hypothesized that it's because we've intrinsically linked money to food; when we are poor this our primary use of money. When someone is hungry all other secondary needs are put on the shelf.

TLDR: It's expensive to be poor, it's harder to make rational budgeting decisions when poor.