>The same applies to tanks, artillery, and pretty much everything else.
It literally does not.
US built 6700 Bradleys. US built 10,000 Abrams. Thousands of these machines are already stationed in Europe just waiting to shoot Russians.
Germany built 3600 Leopard 2 tanks. They built 2k Marder IFVs.
Saab built 300 Grippens.
The Brits alone built over 400 main battle tanks. France alone built 800 of theirs.
You should divide all these numbers by half or more to estimate ones with modernization upgrades, but Russia ran out of modernized equipment a while ago, and NATO 80s equipment has demonstrably outclassed Soviet leftovers.
The US is bad at producing Artillery shells because we utterly refuse to use State power to induce business nowadays, because of stupid "Capitalism good, gubermint bad" ideology, but Europe ramped up shell production. Manufacturers have openly said that all they need is a commitment, and they will build capacity.
The anti-air missile problem is because NATO always intended to rely on US air power (and our thousands of aircraft) to utterly own the skies and deny any air attack. Also the Shahed situation is somewhat novel. The US once produced 40,000 HAWK Anti-air missiles, which would be perfectly sufficient against something like Shahed.
Nobody wants to disarm themselves to give everything they have to Ukraine, but there is substantial arms that are just waiting for use, while Ukraine suffers. US alone could arm Ukraine twice over and not even feel the pain. Most of our equipment is considered not useful against China and is slated to be replaced, but we STILL refuse to sell it.