Firstly, this question points out the reality and that is the fact that the Wehrmacht appeared to be a modern and a highly developed fighting force.
But that is not 100% correct.
The German army in WW2 war more like a mixed bag.
First off, to cut out any confusions, most pictures that you see on the internet and look like this. They were usually especially taken for propaganda purposes.
The Wehrmacht wanted to appear as an invincible fighting force to the German people. Only about 20% of the army was mechanized and motorized, the rest was using horses.
The legend of the invincible Wehrmacht was largely a myth created by effective logistical and aggressive strategic command early on in the war. From a logistical and strategically point of view, equipment and supplies were horse drawn behind the frontlines and the advanced units were focused on spearheading enemy weak-points in the Blitzkrieg fashion.
They were decisive in combat and good at maneuvering in aggressive pushes so that the enemy only fought their best troops. This strategy worked out well especially early on in the war (1939–1941).
Moscow and Stalingrad showed a more realistic face of the German army. By the time of Barbarossa the Germans had enough tanks, but not nearly enough vehicles for such an extended front. To make matters worse, mechanized troops needed lots of oil, which Germany wasn’t so keen on giving away easily.
(this is what you were likely to see on all fronts, in any year of the war)
The Wunderwaffe program was something different. Germany was ahead in Jet engines, missiles and heavy tank technology because the Treaty of Versailles did not cover this issue. However, as most historians say, this was too little and too late.
‘The net result of all these weapons, deployed or otherwise, was that the Reich wasted a lot of money and technical expertise (and killed a lot of forced and slave laborers) in developing and producing exotic devices that yielded little or no tactical and strategic advantage’’
