Comment by maratc

The problem with your argument is that the price to the consumer stays the same, regardless of the payment processor involved (or cash when none are involved.) These are the rules set by payment processors. With these rules, the prices will stay the same with any amount of the supply. If these rules are changed, all payment processors will suffer in cash's favour, and as governments oppose cash-based economy for tax maximisation, the change of the rules is unlikely.