Your mistake is in assuming the bank is who reimburses their account holders for stolen funds. It's not. Every store your card/account was used at was forced to return those funds to your bank, even if they already provided the products or services that were purchased. They also each had to pay a chargeback fee (usually $15-20).

Say your credit card is stolen, and used to purchase 5 items from 5 stores. Each of those 5 stores will be forced to return all of the money they charged, no matter how impossible it might be for them to know the credit card was stolen. They will also collectively pay $100 in chargeback fees to your bank, which is likely more than it cost to move the couple pieces of paper it took to handle the situation and inform the customer.

The bank has now made a profit.

Each store that accepted the stolen credit card has lost:

- The payment they accepted

- The transaction fees paid on the payment they accepted

- The product they shipped, potentially hundreds or thousands of dollars

- The chargeback fee

And if chargebacks ever amount to more than about 1% of any of those store's transactions, their processing fees can go up, they can have their cash flow abruptly cut as a reserve fund is created to hold their future charges for some time, or they can lose their ability to accept credit cards entirely.