To my knowledge there will always be a need for counties to maintain there legacy systems.
Till they come out with a 800 Mhz. Trunking pager they will still need a way to alert volunteers for calls.
The only way I can see them getting away with their VHF system is to provide every firefighter in the county with a 800 Mhz. radio. I don't really see that happening with volunteer fire departments just trying to make ends meet for operating cost. (ie. Insurance, fuel, equipment maint.).
Now they could do like a lot of other counties in the state, using the VHF channel for paging purposes and then assigning an 800 Mhz. operations channel for the duration of the call.
But still firefighters that don't have a 800 Mhz. radio are still screwed unless they have the money to afford a high dollar digital scanner.
I think there is a patch for the VHF Fire Channel across the Onslow 800 Mhz. System.
Hope this helps
David