While we live in the fantasy land that they are quite smart, but happen to be poor we really can't move ahead and improve the situation, the two issues are linked.
Someone well off might also may not have the mental capacity, but it will affect them less, I get that but that's an aside until the far future when everyone is well off.
IE Using disposable diapers rather than reusable ones? It is kinda scary the article has this as a given.
I get as a single parent time is hard to find, but it also means less shopping. True you have to have a washing machine, but surely responsible use of a credit card allows would make this cheaper and easier then going to a laundromat.
Responsible use of a credit card is hard and this is more the issue, not a strict lack of money problem.