UK admitted they have ammo for 3 weeks of warfare. German military is in shambles. French and Polish disarmed some of their units to send arms to Ukraine. US is not in such a great condition too, eating L after L from barely armed people like Taliban or Ansar Allah.
Sure, they may be well armed but for usual aerial terror campaigns (because not even for naval now), but absolutely not for land warfare.
If the United States had the capacity to make enough ammunition and ordnance to fight multiple wars at the same time, there would be enough people employed by these companies that you would probably personally know at least 1 of them.
A very large portion of American military doctrine is centered around avoiding overextension.
And yet they are currently already overextended.