Plane swapping AKA lets disrupt maximum passengers possible

Arrived early at terminal & only one check in operating. Bit of a queue but no big deal. Advised flight delayed 1/2 hour . Again no bigdeal. We noted that Sydney flight delayed. Waited until 12.45 for boarding - still only half an hour behind . Then they swapped the Melbourne Plane for Sydney. When queried the Jetstar staff they advised in was ok because " we do plane swapping all the time" . As I sit here at the terminal Sydney still not departed over 2 hours late. No sign of the Melbourne plane if on time will only be 2-3 hours late. Well done to Jetstar - managed to delay every Jetstar passenger leaving here.