It boils down to nobody bothering to take the matter in hand and address it. A sluggish attitude that might be expected in peacetime, but in war is inexcusable.
But then the scandal of allied anti-tank guns pales beside the scandal of allied tank design.
http://www.amazon.com/Great-Scandal-.../dp/0112904602
One might wonder why the 3.7 inch gun had to be almost twice as heavy as the Flak 36?