Historically a lot of restaurants and retail establishments in the US had minimum charges for credit cards. My anecdata is that this is far less common today (Brooklyn notwithstanding).

There's also just been this psychological shift that makes it generally OK in most places to put that $3 salad on a credit card. I'd never have done that 10 years ago. Now I routinely charge my lunch or a cup of coffee.

I don't know how much of this is changes to credit card fee structures and how much is that it's just become a cost of doing business many merchants now feel they have to put up with.

We had that in the UK for a while too. It seemed that the big corps ended up absorbing the fee and then most others had to too. There's still the occasional merchant that has a minimum but I see less and less as time goes on.

In theory, our interchange fees were reduced, but from what I saw it just resulted in most decent cashback schemes disappearing. This seems to have resulted in issuers making the same margin as they no longer pay out a part of it to the customer.