That's if they pass on the cost to the consumer. Some businesses charge the same amount whether paying cash or card, meaning paying with a card is ""free"", or at least not "penalized" over cash.
I, as a cake seller have a cost i need to pay to the network every month, from my total revenue it's some percentage (depending on ratio of cash vs card). I obviously add that percentage to my cake prices to make up for that. Both cash and card payers pay the same amount for the cake, thus they share the price hike equally.