All businesses build all their costs into their pricing, except for some reason credit card surcharges.

Surcharges for public holidays (where staff cost more) are common. When you buy something online, you pay for shipping separately even though every item needs to be shipped. Air BnBs often have a mandatory cleaning fee. Air NZ has in the past even charged a fuel surcharge, as if you could somehow fly a plane without fuel.

There are lots of costs that should be built in but aren't. I think these are all examples of things that should be built in more than a credit card fee, since the cost of the service actually changes depending on if you use a credit card or not.

Someone’s making bank.

So mainly it's the bank itself, but it's also important to know that rewards are paid for by the fees. So if you get airpoints or a cash back of 1%, that e.g. 1% came from the 2% fee that you (or the business) paid. Though I myself make a decent amount from rewards, I'd be much happier if there were no rewards and fees were a quarter of the size.