@georgeob1,
The Germans weren't using the Pzkw IV in 1940 in France in any significant numbers (fewer than 150 had been produced by May, 1940), because its performance in Poland lead them make significant chassis alterations, and the performance of the 37 mm guns against British Matildas in France was so poor. The Mark IV model with the 50 mm gun which was to become the German main battle tank for years, until it met heavy columns of Soviet tanks, went into service in September, 1940, after the fall of France. As well, the French fighter aircraft of 1940 could perform with the Messerschmidt Bf 109.
The problem with both forces was in their deployment, which you have alluded to with regard to their armor. They were deployed in a supporting role for infantry divisions, many of which were themselves "static" divisions with no motorized transport of their own. Even Guderian saw his Mark IVs in a supporting role, and many of the early models were armed with a 75 mm howitzer for use as mobile artillery. Guderian looks more brilliant in hindsight, though, as is so often the case with military men. The British Matildas and Valentines, slow, lumbering beasts, were almost impervious to the German AP rounds from their 37 mm guns, and were impervious to the HE from the 75 mm howitzers. This lead to the improvements in the Mark IV which made it a good, if not a great main battle tank for about a year--until they encountered the Soviet armor in significant numbers.
Guderian saw two things which were to have a strong influence on his thinking, and on the design of armored fighting vehciles. One was that the earlier Pzkw Is and IIs, which used gasoline engines, were able to fill up at French and Belgian service stations and roar on down the road, making a reality the mobility which Guderian had previously only dreamed about--and the static defense of Belgium and France showed how fatal it was not to at least be prepared to be mobile.
But when the Matildas and Valentines could get a good shot at the Mark Is & IIs, they often "brewed up" like roman candles. So the other thing the Germans learned was to stop using gasoline engines in their armor, and to switch to diesel. A diesel-powered tank could still catch fire, but the crew had a chance to escape, and if you could hold the battlefield, the hulk could be salvaged either to be rebuilt or to provide parts to scavange.
What doomed German armor eventually is that they became "over-engineered" with the Tigers and Panthers in response to Soviet armor, so that keeping them maintained in service became a nightmare; and the simple matter of the logistics of providing fuel for such behemoths proved impossible. When German engineers went to the Soviet Union to look at the T-34, the front-line armor officers begged them to just build that tank for them. Instead, they got Tiger tanks, and there were never enough. Between 1940 and 1958, the Soviets built more than 80,000 T-34 tanks. The Americans built more than 50,000 Sherman tanks. In Normandy, the German soldiers would say that a Tiger tank could kill ten Shermans before they got him--and that the "Amis" always had at least 11. The Tigers and the Panthers were engineered beyond the capacity of Germany's industrial base to manufacture and maintain in sufficient numbers.
De Gaulle, whom it seems everyone in World War II on the Allied side loved to hate, constantly carped before the war about the dispersal of armored units and air units--he called for their concentration to make them more effective. However, that concept was anathema to the static defense in which the French military had become intellectually invested, so he was ignored. What do young cavalry officers know, anyway?
