In Maricopa County alone, there are AZWINS, TOPAZ, RWC, and MC - P25 as sole systems.
Not a lot of interoperability there for the end user.
RWC has G, H & 2 other decks for interop.
Plenty of interop choices with area wide trunking coverage.
I admit the agencies are not using the systems to their full potential. Patches can link every AZ system if they wanted to.
There are plenty of officers who monitor a few RWC interop. They use it for basic chit chat. Waiting for a pursuit or SWAT call etc.
For RWC. A talkgroup is dedicated for the racers. Officers will respond to groups within sourounding counties where RWC covers.