The AD operator does not have to own and operate the ARFF. They can contract it out to the provider. Have you considered that our gold plated Part 139H is actually a bit over the top for most aerodromes?
I'm not defending the situation - just informing that ARFF is established per current CASA regs.
I seem to recall some years back Airservices or its predecessor CAA tried to divest itself of ARFF but no-one wanted to take it on.