For all the hype on armoured cars their use in an armoured battle is more of finding the enemy and occasionally shooting at something they could easily handle like say a platoon of infantry or a few trucks in a convoy . Once this is understood it is easy to see that the vaunted German armoured cars were utterly useless to improve the speed of advance . Now as other posters have said if the mass production of a common chassis vehicle or even common engine parts etc then it would improve matters considerably . Imagine just how many spares you need to run an army with a different engine and suspension etc for just different classes of vehicle . Now imagine your logistical and mechanical needs are for 50 different truck types , your mechanics need to be actual tradesmen and good ones at that , instead of being trained by rote on a single or maybe half dozen engine types . Cannibalising to keep trucks working can also only go so far .
If you went back in time and tried to make the German army better the first task is to find the people responsible for military logistics and bring them together with a piece of camouflage painted 4*2 as hard as possible . Armoured cars great lets have the same engine family in all of them . Half tracks , great lets make them also use the same engine family . Chasis components like suspension , drive shafts gearboxes etc , lets make them all use the same components .
Oh look one of the 30 factories making spare parts for vehicle A was bombed no spare parts for that vehicle will exist for 6 months , yup that's a smart way to run a war .
