> I don't think I've seen anyone pay with cash in years. Even the old people at the grocery store use chip-and-PIN cards.
I'm not sure where you live. I work in a fast-food place on a college campus. While the students generally use their meal-plans to buy food, the moment we have a "parents' weekend" or similar event, we do a lot of cash.
It is generally poorer people (who don't have access to banks) who have to use cash (or resort to alternative banking systems that charge exorbitant fees).