Have dealt with quite a few Airports in Australia on this one. None want to if they can get away with it due to the cost. Adelaide is the same as Brisbane. It has a couple more days a year of Fog and has had a couple of high profile Fog related incidents but still has nothing better than CAT I. (Which doesn't stop some airlines going all the way to rollout if you have ever sat at the threshold on a murky day).
Even Perth was not keen to spend the money but as a remote airfield in effect for wide bodies there was no choice.
For an Airport Car parks are pure revenue and ILS's are pure cost. Avoid them as much as possible and hope RNP AR CAT III comes quickly.