No one else is funding other peoples money in any significant way. The problem with cash back and miles programs is consumers don’t realize the business they just bought something from is paying the fees which then amounts to the cash back. Essentially forcing the consumer to pay a higher price but it’s their own money coming back to them later. In the mean time the banks hold more cash in their pocket and earn interest until you redeem your rewards and benefit even more when people don’t use their rewards and points, some people never redeem them, similar to gift cards. Then the banks want to seem like the good guys giving your own money from the fees of stuff you bought back to you. It’s all a big unnecessary loop when the price of goods could have just been lower in the first place.