The airlines are following the lead set by the other big travel industry player several years ago- the hotel industry. They reward customers based on $$ spent vs. number of nights stayed.

Business travelers hate paying 1200 bucks for a ticket to sit next to someone who paid 399 and got the same mileage reward, just like Hilton that gave credits for a nights stay at a discount or full rate.

American will convert too once they get their res systems merged.