There is a fee (UK), just you don't pay it, the shop pays it. That's what hits the small businesses - they either have to raise the price of the product to cover the cost of the card machine or pay that from their own pocket. Obviously they will not ask customers to cover the difference.

Don't forget plastic money, when we're promised to use "free" debit cards. There is always a fee, and one way or another we have to pay it. Problem I see is that there is more and more difficult to use cash. All except one cash machines were removed from where I live. The one's left behind 80% of time doesn't work. We're in tech "utopia" trap.