Our tanks weren't designed to fight German armor. That was the job of anti tank weapons, artillery, air power and these;
http://www.britannica.com/normandy/articles/tank_destroyer.html
Then they should not have taken the field against German armor. The Germans only produced about 5,500 Panzers. It appears that we should have depended on our tank destroyers to knock out their Panzers and saved our armor for infantry/armor joint operations.