It may simply not be legal for them to decide to drop customers just because they are, taken individually, unprofitable. Think about an all-you-can-eat buffet.

It may simply not be legal for them to decide to drop customers just because they are, taken individually, unprofitable. Think about an all-you-can-eat buffet. Some poor soul is gonna starve themselves so they can splurge and have a "good deal" on a lot of food. Most people will not, and the business would be in trouble otherwise. They still have to serve the patron who's eating a lot, because what kind of buffet would it be if it was "all you can eat, until you're eating so much that we're no longer making enough money"? Or, some retailers sell items at a very low price, just to get people into the store in hope of them starting to buy more. Nothing stops you from getting into the store, getting the deal on those items and not buying anything else. The store may be losing money on you but they can't stop you from purchasing the item at the advertised price. People who choose to spend their time and energy chasing deals to hyper-optimize the benefits on their credit card savings are entitled to their savings. Companies (credit cards or otherwise) are just interested in the total outcome of their operations anyway, not on making money off of every single customer. (Besides, even just defining what is a "profitable customer" is a hairy problem.)