The reason for no ARFFS at Bankstown, or any of the GAAP's, is thus. They were withdrawn circa 1990 for cost reasons. ie: huge cost, little use.
The ONLY legal supplier of ARFFS is currently Airservices Australia and if there was a desire to re-establish such a service it would be on an economic cost basis. Think $1.5Mill plus per year for Bankstown. Who would pay that? The user? the airport? Thoughts of stuffing a Ute with firefighting gear and having it available for anyone to grab are regrettably pipe dreams. For a start there would be an issue of liability if something went wrong. Then training, then availability. Then insurance cover.
Interesting that Airservices ARFFS covers 21 airports across Australia. How many airports have jet RPT services? Well, 44 airports are required to have checked bag screening for jet RPT services so you work it out.