> How did these people live through COVID and never encounter a QR code they had to scan with a phone?

Was that a requirement? I got through it without scanning a single QR code. I had my vaccination status available as a QR code (on paper when travelling in order not to depend on just a smartphone), but not the other way around.

We just ignored restaurants without paper menus, as we always do. It wasn't the time to eat out in any case.