The thing that annoys me with these articles is the wrong emphasis on the value of those munitions. Too many people think that America just gave that as equal in cash to Ukraine.
In truth, probably the largest amount of that value is in the labour, which is done by skilled Americans. Those Americans then then put that income back into the economy by buying American products.
They're also getting rid of old stocks of weapons that need to be de-commissioned at a real cost to land and the environment (those cluster munitions for instance).
The evaluation of these systems is based on a replacement cost with new ones. Perun said it well with his analogy: "If a tradie was to write off his 25 year old ute at the cost of a new one, that would be classified as fraud."