So the military needs new stuff

Know who else started out with old and out dated(well mainly old and breaking down) weapons? The Founding Fathers when the War of Independence started!

The equipment was the Afghan army’s .

You keep saying that. Is your point that because it belonged to the Afghan army (which no longer exists) that we shouldn't care that the equipment is now in the hands of The Taliban and/or our troops should not have tried to disable or destroy that equipment?

The military's mission boils down to two essential tasks - kill people and break things. A boot Marine private knows how to use an incendiary grenade. One of those babies on a HUMVEE's engine block will render that vehicle useless in 10 seconds.