“It should be simple.”
Should be!!! But it never has been that way in Afghanistan. Why?
Since Korea we have refused to fight WWII style - TOTAL commitment to TOTAL defeat of the enemy, including taking the war to his allies and safe havens, until unconditional surrender. That is the only way wars are actually WON.
NO NATION BUILDING! The comment "You broke it,you own it" is sheer idiocy.