Banks have to want to do the deal so it is profitable for them as well. The majoirty of the credit card users that the legacy airlines have don't really make the credit card companies much money. The "big fish" are what really make it worth it. Those that spend over $100k per year on their branded credit card is where the real profits are. Also, the card holder have to want to use the card for that many purchases. A business owner that uses the card for $20k per month, and then takes a family of 5 on 2 European vacations first class with points at Delta is the target customer for the cards. Not really something that Spirit can offer.

The typical spirit passenger...well...is different.