Fire Engines are big collector's items. They actually have Fire Truck conventions and many run their pumps from a nearby pond all at the same time to put on a pretty good show. Some are also in use for other purposes when not at shows and parades. Irrigation purposes would be an example. It also would be handy for a fire too, especially if someone lives in a dry or a fire prone area.
Then others will take the fire bed off and have a nice looking, low mileage truck for a Flat Bed, Rollback, Dump, etc. I would rather see them stay as fire trucks, but would also rather see them converted instead of just sitting outside fading away.
Bill