According to the very good article on the English Longbow in Wiki (
here), the long training problem really was the problem. English longbows had a draw of 150-180 lbs, something no modern archer can master today and maintain any degree of accuracy. Plus they could fire them at 12 rounds per minute. The strength required to operate the weapon was so great, skeletons of archers are deformed and can be recognized by their "enlarged left arms, and often bone spurs on left wrists, left shoulders and right fingers".
Besides, the French always had the advantage of population, so they always took the "cannon fodder" approach to warfare. Arm a large population with simple weapons and throw them at the enemy. The English didn't have the luxury of a massive population, and so developed a different tradition.