Lonewolf, again going from distant memory, but I think the width of the Sherman was dictated by the standard width of the US rail system - i.e. that it would fit on the standard rail car and fit through the normal rail tunnels and bridges. Hence the relatively tall and narrow profile.
IIRC, the US produced ~50,000 Shermans during WWII, while total German production of Panther, Tiger, and Tiger II tanks was a few thousand.