From another article in the New York Times:
unsustainable rate — especially in places like Bakhmut — under the false assumption that the West’s supply of ordnance is unlimited, said the U.S
Ah, hubris; military planners good ol' friend. Explains why they are on the run to set up shop for 152mm ammunition as they likely can't keep up delivering 155mm without messing their own stocks nor the capacity to produce them at a rate capable of repleneshing both the Ukranians and their own stocks.
Also the focus on 152mm is that soviet pieces seem more durable than western artillery in this type of conflict and the logistics to keep them working are untenable in the medium term to the point is more practical to find a way to restart 152mm ammo production so the Ukranians stick to their more reliable soviet guns.