hmmm, good question. Guess I'll have to take a trip up north and listen for awhile. The last time I was there (about a year ago) Flag Fire was still on the old analog channels. According to Radio Reference it appears PD has moved to the new system and Fire has not. Why not? I could only make a few guesses.
First, not everyone wants to be on digital trunked systems. Phoenix Fire was one of the first fire departments in the country to do a comprehensive study on the benefits (and problems) of the new systems. They quickly realized there were serious flaws and were reluctant to move. After dragging their feet for years they did finally move half their comms to digital trunking, but still use analog for firefighting activities. On one hand it's a pain using 2 radio systems, on the other hand they have the best of both worlds. Research indicates many fire departments are sorry they moved and wish they had their old systems back.
The second thing that comes to mind is the cost and logistics. Flag now dispatches for most of the surrounding communities, much like Phoenix does in the valley. While Flag Fire could probably move to the new system with little trouble, it's a whole 'nother ball game trying to get 10-15 different communities to all convert.
A few rambling thoughts IMHO, as they say.