Because in the US we already have laws that cap the fees on most debit cards: https://www.ftc.gov/system/files/documents/plain-language/bu...

There's even a proposal to drop these fees even lower: https://www.reuters.com/markets/us/us-fed-set-revise-debit-c...

Europe has similar laws capping the fees on both credit cards and debit cards. We could do the same and it would work better for everyone except the credit card companies.