“My recollection was that the battle of Agincourt proved the tactical superiority of well trained lowbowmen, whose skill could take down knights in armor from a safe distance. The longbow, propelling a metal tipped arrow, pierced the knight’s armor. The carnage was the beginning of the end for the mounted knight in armor.”
Always my understanding too. Whether the English were outnumbered or not, a bunch of guys walking around in leather took down a a bunch of guys on horses wearing armor. Horses and armor were one of the main bases the nobility had for controlling the peasants in that era. So it was the symbolic beginning of the end for horses and armor both militarily and as an instrument of oppression.
In fact, I believe it was very illegal then for a commoner to have armor—which just proves that human nature never changes—guys with power always come to the same conclusions.
You forgot another key factor... the terrain. Henry V and his commanders selected a strong defensive position with a narrow front that acted as a funnel. The French knights were increasingly jammed together making them an ideal target. Had the battlefield not been so muddy the French would probably have got round to flanking them out of the postion.