Initially only “credit” networks like Visa/MC supported tap to pay with interchange fees of 1 to 2.5%. The low fee debit networks did not. Regulated debit is as

Initially only “credit” networks like Visa/MC supported tap to pay with interchange fees of 1 to 2.5%. The low fee debit networks did not. Regulated debit is as cheap as 21c + 0.05%. A lot of retailers have thin profit margins of 5%. So contactless adoption would mean more high interchange “credit” transactions and fewer low interchange debit transactions. Thus the retailer resistance to contactless.