The military industrial complex couldn't get rich if any ol body could just pick "ammo" up off of the ground.
It's hard to prevail against munitions using sticks and rocks but it's been done.
Of course, for all our cutting edge technology, all a foreign enemy need do to win in battle against the US in the present time is to disable our force's will to fight by misgendering them, using socially constructed pronouns that indicate their biological sex, and uttering bigoted phrases.
Our troops will immediately run away to seek a safe space, therapy, and a war moderator to issue the invaders a time out.
Keeping Gen X going as long as we can is our only hope for survival as a nation.