Helos don't need to move with the unit. They can operate off semi-prepared areas 25 to 50 km behind the lines and still be as effective and less vulnerable and will not need a dedicated number of men to protect them and maintain them and lug them around in the front lines. They can also be used exactly where needed and if they are not needed immediately for the unit that is lugging them around in a truck. It does not make sense to treat helos like mortar or tanks.
Apache does not have refueling capability..?