A good article, but it omitted how in addition to the SYD aircraft movement limit of 80 per hour, there's a second one of 'no more than 20' IIRC during each quarter hour period. Apparently at times this creates additional delays.
I wonder if air traffic controllers are deliberately taking excessive "sick days" off, and co-ordinating this among colleagues as workers at the wharves have been known to do.
I'd be certain airlines cancel one flight if it's going to be poorly patronised on a high frequency route, provided it can handle the resultant passenger loadings in each direction. There doesn't seem a pattern to this: we might think that the xx15 and xx45 timetabled departures were the first to disappear, but that doesn't necessarily occur.
The punctuality on MEL-SYD-MEL, a separate problem, is also often poor. It never approaches the excellent level of many overseas high speed rail operators.
