US military ain't some unstoppable force in all possible scenarios, it was stopped and won over quite a few times, last time I recall by taliban sheepherders. In some cases like first Iraq war yes, but they don't wage those wars anymore. And all mental limits re casualties are very real limits just like other.

Its like saying russia could/can conquer whole Europe, if only X, Y and Z. That effectively means they can't, as we see playing out right now despite them trying desperately to achieve this very thing.