An article on DoD Buzz about the Air Force's next-generation aircraft states:

Meantime, the operational costs of the F-35 are unlikely to affect how many of the aircraft the service intends to buy, Donley said.

The cost of flying the F-35 “will be slightly higher than the F-16, there’s no doubt about that in my mind,” he said. “I don’t think there’s a link there between projected operational costs and how many we’re going to buy.”

How can there not be a link between what an aircraft costs to operate and the quantity that the Air Force will purchase? Isn't the cost of ownership a key component of fleet composition and size?