Not much need to wonder. At least, I’m not wondering.
That said, NATO doctrine is to achieve air supremacy and use that advantage to exploit combined arms breakthroughs against enemy defense. A big WWI-style static artillery duel like what is happening in Ukraine isn’t what they are planning for and probably isn’t what they should be planning for.
FWIW, I read an analysis that concluded that Russia’s limitation won’t be artillery shells, it will be artillery tubes. They have an enormous number of them, but at current rates of fire they are wearing out quickly and Russia has a very limited ability to manufacture new ones. Similarly, the Russians have huge stockpiles of tanks which they can refurbish, but brand new tanks are coming off the line in a tiny trickle. Far short of the replacement numbers needed.