True, you can degrade the enemy’s will to fight, but I didn’t mention that, since it’s not going to happen in a situation where you have placed the invaded country in existential peril. So the Russians screwed themselves on that count as well.
“True, you can degrade the enemy’s will to fight,”
It’s a lesson we have learned to our cost in Vietnam, Iraq, and Afghanistan. If you are invading someone else’s home the level of casualties they are willing to accept in exchange for victory is essentially infinite.