Keep in mind that the U.S. and the West are reliant on China and others, not only for ammo but even for various needs, like fossil fuels and minerals.
https://foreignpolicy.com/2023/03/16/us-military-china-minerals-supply-chain/
https://www.voanews.com/a/putin-profits-off-us-and-european-reliance-on-russian-nuclear-fuel-/7220368.html
https://www.rferl.org/a/russia-natural-gas-european-union-dependence-ukraine-war/32754244.html
It's only later that they called for bans, but with a lot of concern because their manufacturing base is not prepared to go on a war footing, and they lack oil and minerals to maintain middle class lifestyles. (There's one report which even shows that the U.S. is wholly unprepared against China because its industrial base is shot.)
Meanwhile, many don't want to serve in the military, if not unfit to serve:
https://www.euronews.com/2023/09/01/conscription-is-seeing-a-revival-across-europe-is-that-a-good-thing
https://www.military.com/daily-news/2022/09/28/new-pentagon-study-shows-77-of-young-americans-are-ineligible-military-service.html
One expert even pointed out that most U.S. youth are not even fit for many careers, and the main reasons involve drugs, alcoholism, criminal records, unwanted pregnancies, poor physical or mental health, obesity, and low test scores.
Lastly, there has been growing distrust of the West by the Global South, as seen in moves away from the petrodollar and increasing bilateral trade, and what appears to be the emergence of a multipolar global economy.