The following is based on content cut from Red Alert 2 and has not been confirmed by canon sources.
The Alliedturret was supposed to be redesigned for Red Alert 2, but as development progressed it, was cut. A possible explanation was to give way for the Prism towers, which fulfilled a similar anti-armour role. Another explanation for using Prism Towers would be to create a similar design for the Allies against the anti-tank and anti-infantry Tesla coils. This could be true, as the turret was weak against infantry whereas the Prism Tower was not.