The “West” doesn’t have the shells to give and can’t make them in sufficient quantities.
The factories and tooling takes years to build with the first couple years of the “Special Military Operation” have been frittered away. Not so on the Russian side.
If we wanted to build a new munitions factory in the United States, the environmental impact study alone would take a decade to complete before the first slab of concrete was poured.
It isn't the 1940s anymore.