A tank's primary job is not to fight tanks; it is a manoeuvre weapon. I.e. its job is to get through a whole in the enemy lines (probably made by arty and infantry) and to smash the rear areas and force the enemy to retreat from prepared positions - to force infantry out where artillery can kill it.
Thus the M4 Sherman, an excellent exploitation tank, with excellent reliability, and a great 75mm to use against infantry
The M3/M5 Stuart, a fast scout tank to find those areas
But the M6 Heavy Tank, needed for the initial Breakthru, when no hole was present, wasn't produced. P-47s and 155mm LongToms can only do so much.
And TDs were to do the fighting against other Tanks, independent of the Divisions CCA or CCB. Sometimes they were in the right place to act in that role.
A US AD was used like a Nazi Kampfgruppe, but without breakthru Panzer Company like the Tiger, and Sturmgeschütz assault gun Battalions.
That why even Patton had trouble with areas like Metz. Wrong tools.