I think I can speak for everybody when I say
American tanks during WW2 sucked
That's a cold war tank and was a response to the IS-3 and T-10 series of heavy tank. Infact the American M103, British FV214 Conqueror, and French ARL 44 were all a response to heavy soviet armor. However with HEAT warheads and missiles becoming common around the 1960's many armies abandoned the weight classes in favor a main battle tank that could do everything. So the NATO Armies adopted first gen MBT's around the 1970's like the Leopard 1, M60 Patton, AMX-50, and Chieftain. The T-55, T-62 were one of the first PACT MBT's, later they were phased out with the T-72 and the T-64 which was reserved for the elite armored regiments. Some armies still used light tanks, but they were used for limited recon and infantry support.
