They just keep extending credit until they're right. It cost them nothing to extend you credit and pretty much one interest payment makes up for it. The perks t

They just keep extending credit until they're right. It cost them nothing to extend you credit and pretty much one interest payment makes up for it. The perks that offset the annual fees on their fee cards are just an accounting gimmick on their end. "Oh cool Audible gets to print awesome revenue numbers while we just pay back the customer that paid who feels like it makes their annual fee worth it" and who knows what arrangement behind the scenes is, shares? More targeted customer data? And if you actually are spending, as you suggest, they make enough from the merchants who are eating the 3% transaction fee. You're the data product, like every other cool free thing over the last decade, and they have a sustainable business model. And if you ever do have a disruption in your earnings while you are floating a balance on the credit card, you've just become their whale customer that is paying for the whole operation with interest. By the time you default they really don't care about collections because they've already made so much, they're very ready to sell off the debt to some collections agency for pennies. You can be the most meticulous and responsible user of debt, and still have this happen to you eventually. They're just the house in their credit casino and all they have to do is wait.