A friend of mine owns a restaurant that is pretty remote so lower business. He told me he doesn't take credit cards because he would be paying them a percentage for everything.
It is kind of like the mafia to a small guy like him.
I think he does do a few phone apps.
A waitress at another cash-only restaurant told me, worse than customers who hear they won't take credit cards are the apple pay folks. "They really get annoyed when they don't get their apple pay"
Franchises don't care. They can raise prices monthly or even dynamic price if they want to.
Kind of sucks for society because lots of the best/greatest restaurants are not franchises.