The size of the packages being sent now is only a fraction of what it was last year. The reality is that the MIC in US is simply unable to produce artillery shells anywhere close to the rate they're being used at. This is primarily an artillery war of attrition and the west is not able to keep up.

When they were getting the Ukrainian offensive going, US had to pull shells from Israel and South Korea already. This was supposed to be the big breakthrough for Ukraine, and NATO threw everything they had into it. Now that the offensive fizzled, there's really nothing else to be done.