Points sold to the credit card companies turn into a cash asset, while the points earned by flyers are solely carried as a liability. The net redemption cost to the airline for any point is the same, but one generates cash income as a line item when created, and the other is really just a percentage of the profits being realized from a ticket sale converted into a liability. With the ratio of points earned linked to ticket price, I don't see any way for flyers to "change their buying behavior" enough to ever make a difference by themselves, unless that percentage of the ticket price that covers the points is increased, or the amount earned from the card companies per point is decreased.