Its not the time as much as the experience gained and a system to reviewed performance. When the Germans first used armor in Poland, the plan insisted on having a panzer korps spearheading each infantry army route of advance. Based on the performance Poland, it was judged that this was a waste of resources, so panzer groups were formed for the invasion of France to act independant of infantry armies.
Other countries saw this and learned something , but not what the Germans learned. Its unrealistic to expect the French, without any of this experience , to have drawn the same conclusions as the Germans ,in even less time than the Germans did. Perhaps after the German invasion of France, they could have integrated these lessons ,given enough time and effort. But that would require a different pod.