Hmm, so isolated for 737 operations, when you could go to Busselton, Kalgoorlie, Pearce. Add to that possibly Albany, Esperance, and a few other 1800m+ strips that can handle jets. Pearce is viable, a QF group landed and refueled at East Sale a few years back when it got caught out by weather in Melbourne, I don't recall the RAAF was particularly phased by it being used for such purpose given the circumstance. The question in this riddle is why the jet did not proceed to an alternate for fuel, and rather declare a Mayday to proceed to it's nominated destination. Were the alternate destinations ruled out, were they led to believe there was going to be no more holding and then told last second there was more, say after passing the pnr for PKG. The report will have all the answers. Is it OK to declare a fuel mayday to push to a destination when an alternate is available? again something for the ATSB to ponder over.
IF Perth was truly isolated for the day, due to every other port in the area being fogged in or not adequate, then surely the extra fuel required for travel to an isolated aerodrome would need to be carried, add to that EDTO requirements.