Because you still need to maeneuver those forces and the required skill set and difficulty in doing so in no way changes. You still need fancy footwork just as much as when you outnumber the enemy then when you had equality or even. Maneuvering tank divisions in combat requires the skills to maneuver tank divisions in combat, and whether you have one or a dozen of them doesn’t affect that one jot. Similarly, the skills required does not change when you have less then the enemy.



What does change when you have numerical superiority is your margin-for-error. You can afford to make more mistakes, suffer the consequences, and still come back for another go. The inverse is true when operating at numerical inferiority. All being outnumbered or out numbering means is that you can’t or can afford to lose more. But being able to lose more (or less) is not the same thing as being able to win .



Except they don’t. An examination of the tactical-operational methods show that the side with manpower and material superiority did not simply bludgeon their way forward. Instead, they developed tactical and operational skills that allowed them to get things moving again and affect maeneuver warfare.



We do have examples of a war where the side with overwhelming manpower and material superiority was incapable of doing anything more then bludgeoning their way forward on the tactical-operational level, like the Iran-Iraq War. The result was that we never saw anything like Cobra or Bagration or even the Hundreds Days.



And the problem they ran into is that you need to do more then that. Firepower can damage and degrade the enemy, but to destroy him you have to move forward, storm his position, and hold them with manpower.



Which in the end required a willingness to accept casualties closer to that of the Soviets then the WAllies.



No, they did not suffer losses on the order of a third of their forces in a single day, save for where they suffered grievous defeats in the early war when the Germans would outnumber and outmaneuver them. The British disbandment of force’s toward the end of the war had nothing to do with the British (nonexistent) casualty intensive practices and more to do with the fact their manpower pool was so low that even their casualty-averse method of fighting had depleted them.