The security fees did not increase the gross amount that fliers were willing to pay; therefore these fees came out of the hide of the carriers. In fact the gross prices I paid last week for a bunch of Southwest tickets, all the new fees included, were the lowest I have paid in over 4 years.
A fee holiday will go and should go to the carriers as they increase the net price to keep the gross price the same. Look for plenty of articles by economic illiterates complaining that the airlines are gouging passengers.