$80 billion?
That sounds high.
Maybe that is the total cost of supporting Afghan troops.
An Abrams tank might cost $10 million.
I think that is the equipment and support facilities in totality. There were huge amounts of equipment just left there without even a thermite charge dropped into them. Not just tanks. Everything down to and including SAWs, shoulder fired missiles, etc.
I believe that would add up much quicker than you think it would.