Airlines are much more conscious of fog when operating into YPPH, back in the old days, crews had set criteria when operating into Perth. If these were not met, an en route diversion was required.
A while back I two hours out of PER from the north, suddenly 300M FG appeared on the forecast. DJ and QF inbound from the east, diverted to Kalgoorlie without even trying to get in. I continued as I had YPKG and YGEL as alternates and landed with 10km+ but the conditions were perfect for fog to form.
Perth has had a lot of attention from airline flight planning departments due to its isolation, lack of alternates (especially wide body) and peculiar weather.
Perhaps it's time to take a closer look at other airports.