Postal banking would be a good solution. It would allow the post office to offer basic banking services for folks like this that can't access it at commercial institutions.
If USPS banking helps the unbanked by only 50 units of help instead of a maximum of 100, it’s still a 50 point improvement. If Morgan Stanley or JPMorgan can offer me a better banking deal than the post office could, that’s no reason to not have the post office offer banking.
I agree it should be open to everyone, but don’t agree that there can be a maximum of zero-point-zero difference in customer base vs other banks.