The benefit other airlines have with "getting back on track" in a fog situ at SYD is the ability to cancel flights. QF and DJ operate high frequency, up to every 30 mins on some routes, so cancel a couple of MELs or BNEs, redistribute the pax and hey presto. QF also has a lot more slack in its schedules. DJ and JQ have it harder consistently running 30 mins turns with little aircraft downtime.
For JQ the ability to cancel flights is a bit harder though lack of frequency. In many cases the flight in question is the only one, or one of very few in the day ie no where to reaccommodate the pax without making things a bit messy (eg the HTI situ). For JQ, only SYD-OOL realistically has the frequency to sustain cancellations.