I don't get it -- Amex and Discover are still providing healthy competition, so the "duopoly" the author complains about seems to be largely irrelevant. Competition between cards is thriving and consumers benefit -- witness the miniscule transaction fee the credit card companies keep after paying your rewards back of 2% to 5%, when you pay your bill on time. The article's main point is that such large companies are a…
Imagine if companies charged 2-5% less because they didn't have to fund CC company marketing tools like cashbacks.
No one cares about numbers like that. That's way, way below the convenience threshold for a typical consumer. Most of us, me included, would rather pay an extra 3.5% than fiddle with deciding on which card to use.
Which is to say: the market has spoken. We've settled on the duopoly not because it's a trap but because it actually maximizes utility. The uniform convenience of "credit cards just work" has quantifiable economic value. And it turns out to be somewhere around 2-5% of the transaction.