You might be right about the aircraft and some of the vehicles, but we probably left stockpiles of spare parts, technical manuals, and ammunition behind too.
With more than half a million machine guns, assault rifles, and hand guns left behind, are you saying they are useless now?
technical manuals
—
Perhaps technical manuals will be useless, considering that most tribal Afghanis have trouble grasping the difference between left and right, to say nothing of being able to read or read English.
Millions of machine guns, assault rifles, RPGs, and hand guns are available worldwide from arms dealers. The only difference is they got them free.
Leaving behind stockpiles of spare parts is not a fact, but an assumption.