Who knows, maybe their argument is that works against the image of convenience for customers? You’d have to go ask them, but it might be proprietary information.

Card processing companies provide a convenience, for which they charge a fee. If it was such a big deal, businesses would not sign on, and many don’t because it doesn’t work for them.

Enough businesses decide that the extra set of customers they can draw by accepting credit cards is worth the 2.5% processing fee, which is why credit cards still exist. It’s not some kind of extortion racket.

Do you think we don't know how Nash equilibrium works? The fact that the rules of a game can be adjusted to drive it away from optimum -- far away, sometimes even to the opposite extrema -- is a pretty basic economic concept and this is a pretty basic example of that concept. Market inefficiency 101 type stuff. That's why everyone else here is focusing on the metagame.

And no, 2.5% is not typical. Maybe Walmart gets 2.5%. I've seen between 4% and 15% in those few instances when the man behind the curtain has been distracted and true rates have snuck past his veil of secrecy.