Working with cash is not free either, you need security truck and drivers that come pick up cash at end of day...
Afaik in EU debit cards are capped much lower than 3%.
If they weren’t turning a profit, they wouldn’t be pushing this.
It's not mutually exclusive. For example, if the operating costs of a cashless system are 1%, the operators charge 3% and cash costs business 5%, the operators turn a profit while it's advantageous for businesses as well. If businesses lower prices with the 2% they saved, it's advantageous for consumers too.
I disagree with those figures. In my experience handling cash is not nearly as expensive as transaction fees.