cat3 only needs two A/P's
73's have been cat 3A for years with two A/P's. then there is cat 3B and cat 3C. different minima.
i suppose the real factor is MONEY-and cost versus return.
the flight crew training manual for the 73 does indeed mention fail operational, but it also mentions HUD's and other bits and bobs that one must purchase to put on board along with authorizations that require money and training.