Do you think airlines like to be delayed? They are in no way in business with the airport stores. A delayed flight affects their entire system for up to 24 hours sometimes - rare cases even longer. It affects every flight that plane will fly that day, and any flights that use the delayed gates. The airlines do not like delays as it hurts their image, puts undue stress on their employees to sort the resulting mess, and it costs them money and raises their overhead.

Airlines want nothing to do with delays, but due to the complexity of the game, there are so many variables involved with a flight pushing out on time, where if one in the chain breaks, the flight may be delayed. You would be surprised how many people and how much coordination it takes to just move one flight.