The last I heard was that AAF wasn't interested in AFRRCS because they had a functional system with Firenet. Maybe they're only on AFRRCS because all GoA entities are expected to take part.
Logistically it's also more difficult to make a trunked radio system work for all the components of a Wildfire organization. Aircraft already come with basic, frequency-agile analog UHF/VHF radios, so they can talk on Firenet all day long when it comes to doing tanker work. Imagine if we had a fire of the size and ferocity that needed some group like Tanker 910 (a DC-10 based tanker system) or the GST (Global Supertanker, a 747-400 based tanker) and our only option was AFRRCS.
Similar issues would hound deployment of foreign ground-based attack crews (though the cache of AFRRCS radios the system has available would make that a little easier).
I suspect there's lots of life left in Firenet at this point.