If I interpreted the first article correctly, the main obstacles are bureaucratic, not lack of industrial capacity. In other words, the article didn’t say “cannot supply” as in missing delivery dates. Mostly just that the bureaucratic process takes a long time.
Congress gave the president the power to bypass the normal bureaucratic process in regards to Ukraine. So thinks like HIMARS, Javelins etc. get send right away as soon as the president decides to send them.
Some equipment is coming directly out of inventory, like the HIMARS and M777s, etc. And some stuff is being built directly for the conflict, like the Abrams that were recently announced.
I think Zeihan is pretty much correct. Lots of equipment like Humvees, M113s, and Bradleys are scheduled to be phased out and replaced anyway. So it doesn’t really cost us very much. Plus that equipment was designed and built in part to counter Russian aggression. It fills that role much better in Ukraine’s inventory than in ours.