The US military has long been obsessed with World War II era tactics. Which essentially amounts to "We've got more troops than you, and we've given them bigger guns".

But this strategy hasn't been relevant since the end of the Cold War. Why would I care how many soldiers you have stationed at an important facility when I can just blow said important facility up with my big bomb? Their presence is irrelevant. Now that drone combat is so prevalent the number of troops you have is even less relevant.

Iran has essentially managed to defeat the United States without any of their troops moving beyond their border.