Mel_Traveller, you bring up an interesting point.
I do wonder if there's a link to cancelled flights and the delay to the next service and a connection with the loyalty of those passengers.
If your syd-mel is cancelled, you wait maybe 30-60 minutes for the next flight - almost every status pax would have encountered this in their domestic travels. Like you allude to - long haul travel with low-frequency services is another story. I wonder what the greater impact is outside of that one particular affected flight. (Insurance companies, hotel rooms (both unused at destination and extra requirements at departure point), crew re-timing and re-positioning, staff at the arrivals end being paid but having no actual work to complete... the financial cost of low frequency could potentially be quite high.) I'm day-dreaming again, off in big data land of what ifs...