When people generally carried cash they would’ve been reluctant to pay with a card if it was 2% more expensive.

When banks provide a business with a card reader, they want that business and it’s customers to use it - if customers continue to use cash then the bank isn’t getting 2% on those sales. So they did their best to avoid card charges being passed on to the customer. The business would pay the 2%, and just build it in to all their pricing.

Depending on jurisdiction maybe the clerk could add a card fee manually, but my point is the merchants weren’t encouraging it.

Now that people generally don’t carry cash, the banks / merchants are in competition with each other rather than competing with cash. About 5 years ago a new merchant / card facility operator emerged in Australia which gave businesses the option of automagically adding the charge to sales, so the customer would pay instead of the business owner.

For a restaurant or something that’s a pretty great deal. For even a relatively small restaurant with a half dozen staff, it might be a third or half of one annual salary in savings.

The majority of restaurants in my area have changed over to merchant facilities offering this type of fee structure.

In the long run, customers aren’t really paying more. Restaurants are always going to charge as much as they can. If every restaurant is doing the same thing then everyone is on equal footing, charging as much as they can, just like before when everyone absorbed these fees.