Why were the Germans in WWI slow to develop tanks and then in WWII infantry anti tank weapons, and the simple answer is need. In WWI the Germans had by 1916 decided that they were going to follow a basic defensive strategy in the west, and they had no need for what was essentially a short range breakthrough weapon. While in the east given just how primitive the early tanks were, and how open the front was, tanks were definitely more of an hindrance than advantage. Thus they didn’t need tanks until mid 1918, having seen what tanks were capable of, and having decided that only by a major offensive could they achieve a favourable settlement to the war in the west. They in addition to making use of a number of captured British tanks, they used a number of their own, which had been deployed with a very low priority. In WWII the situation was in many ways reversed, as up until 1942, it was the Germans who were very much on the offensive, and they were basically content with their two infantry anti tank weapons. The Panzerbluchse 39 anti tank rifle and the 3.7 cm Pak 36, anti tank gun, which given how little they had to go on the defensive, were basically sufficient for their needs. Unlike the Anglo Americans, who having seen just how ineffective their infantry anti tank weapons were, the Boys anti tank rifle, the M2 .50 Browning HMG, and the British 2 pounder anti tank gun and the American 37 mm M3 anti tank gun. Having decided that they both needed a man portable anti tank standoff weapon, the British developed the PIAT and the Americans the Bazooka . The Germans, had decided that their Pak 37 was after encountering the much heavily armoured British Matilda, the French Char 2 B, and later the Soviet T-34 and KV-1, decided that they too needed a man portable standoff anti tank weapon. And by using their knowledge of the Munro effect, hints from captured American Bazookas, along with their knowledge about recoilless weapons, developed both the Panzerfaust and the Panzerschreck. And thus just like in WWI with the initial development of German tanks, so too in WWII, once the Germans needed man portable standoff anti tank weapons, they developed them.
RR.