I'm a little shocked that of all the comments so far, no one has mentioned the financial risk borne by this whole value chain. OP is operating as if it's just a debit system moving money from one account to another but:
- For many consumers there isn't sufficient money in the account to settle all the one-time and ongoing transactions they are liable for -- credit cards are giving you a revolving loan, there's risk it will not be repaid, and that risk ends up reflected in processing fees
- For many _businesses_ managing cash flow is existential -- as merchants they want to be paid as quickly as possible, but as B2B customers they want to have 30-60 days to sell the input goods they've purchased so they can pay for them upstream. There is a premium for that flexibility that gets reflected in processing fees.
- For both consumers and merchants, fraud risk is real and while it's the most solvable part of all this it's a real (and costly!) factor today. That risk for fraud gets moved upstream to the networks/acquirers/processors/issuers and that premium shows up in (you guessed it) processing fees.
If you want to switch the world to a debit-based system where economic transactions are limited by cash on hand, I'd argue that's a poorer and less dynamic world than the one we're operating in today.
- For many consumers there isn't sufficient money in the account to settle all the one-time and ongoing transactions they are liable for -- credit cards are giving you a revolving loan, there's risk it will not be repaid, and that risk ends up reflected in processing fees
- For many _businesses_ managing cash flow is existential -- as merchants they want to be paid as quickly as possible, but as B2B customers they want to have 30-60 days to sell the input goods they've purchased so they can pay for them upstream. There is a premium for that flexibility that gets reflected in processing fees.
- For both consumers and merchants, fraud risk is real and while it's the most solvable part of all this it's a real (and costly!) factor today. That risk for fraud gets moved upstream to the networks/acquirers/processors/issuers and that premium shows up in (you guessed it) processing fees.
If you want to switch the world to a debit-based system where economic transactions are limited by cash on hand, I'd argue that's a poorer and less dynamic world than the one we're operating in today.