We can’t manufacture artillery shells anymore.
“The effectiveness of the escalation in war production is illustrated by the quantities of material manufactured: Britain alone produced nearly four million rifles, a quarter of a million machine guns, 52,000 aeroplanes, 25,000 artillery pieces and over 170 million rounds of artillery shells by the end of the war.”
https://www.iwm.org.uk/history/the-factories-that-fed-the-front-in-the-first-world-war
All America can do now is print funny money and abuse its own citizens.