Well, that was when individual muskets were inaccurate and the coordination issues with commanding thousands of men using drums and flags meant a large mass of soldiers firing in sync could scare the opposing side into fleeing and allow calvary to mop up. And before that, you had knights with plate armor that could could shrug off most bladed weapons on a battlefield that would have destroyed peasant conscript without armor. Warfare's evolved from elite units that could tank almost anything you can throw at them, to using masses of men to soak up more damage than the opposing side, to using cover and squad tactics to evade machine gun fire, to trying to be so stealthy that the enemy can't even fire on you at all. This progression has resulted from modern technology making offense superior to defense in every way. Makes you wonder if there will be a technological progression in the future that begins to give defense an edge over offense.
Defense vs Offense is the quintessential cat & mouse game. If the offense comes up with a new weapon, the defense is forced to come up with a counter. If the defense comes up with a better shield, offense comes up with a bigger bomb.
