The US doesn't care about traditional gun based artillery, and hasn't cared since the Gulf war, it's not a critical part of US/NATO/western aligned doctrine. They're only trying to up artillery production because of Ukraine. US doctrine is all about delivering air support with precision guided munitions. This doctrine was spurred on by its success during the Gulf war where 65 F-111s armed with 4x GBU-12 Paveway 500lb laser guided bombs destroyed over 1500 Iraqi tanks, with the relatively newer F-15Es destroying a couple hundred more with the same loadout (the performance of the A-10 aircraft and M1 Abrams tanks were vastly overstated). Artillery was mainly relegated to counter fire/battery missions with MLRS rockets with DPICM cluster munitions, and ATACMS missiles taking out static air defence sites. US/NATO gun based artillery was vastly outgunned, out ranged and outnumbered by Iraq, yet it had very little effect on the war.

This US doctrine has been refined since then, with the introduction of the 250lb class Small Diameter glide Bombs (SDBs) to replace the GBU-12. The laser guided GBU-39 SDB variant, and the GBU-53 SDB II with a multimode radar seeker, and Israeli SPICE 250 with TV guidance, can hit fast moving targets at distances of 75km, and stationary taegets at distances of over 100km, all independent of GNSS/GPS guidance, and pack a much bigger punch than your average 155mm artillery round. Modern EOTS systems, such as those on the F-35, can track targets at this range from medium to high altitude. A vast upgrade on the 15km range of the GBU-12 and 1990s era targeting pods. One F-35 carries 8x SDBs internally, an F-15E can carry 20 along with two external fuel tanks + two conformal fuel tanks, much more than the 4 GBU-12s per aircraft. Essentially, why have artillery when you have this:

Now this obviously relies on obtaining air superiority, but the US have invested heavily in this area and SEAD/DEAD (suppression/destruction of enemy air defences) capabilities. Stealth strike aircraft also allow for carrying out strikes in contested airspace. How many countries have the capability of stopping an F-35 from getting within 75km of a frontline target and dropping 8x SDBs? And if longer range air defence systems are suppressed, F-15s and F-16s can start doing the same outside of the range of short and medium range air defence systems. In other words, how many missile launchers (and other targets) did Israel take out in Iran, using this class of SDB/SPICE 250, along with UCAVs and Mossad assets with ATGMs and FPV drones, without firing a single artillery shell? Visually verified numbers on missile launchers alone, excluding duplicates and decoys, are around 60, actual numbers likely higher.

Further, I don't think Russia wants to fight an artillery and drone based attrition war, if they could get air superiority near Kyiv and bomb it every day with Su-34s they would, and they certainly tried at the beginning of the war, it's just that the Russian Air Force lacks the SEAD/DEAD capabilities to do this. Ukraine also don't want to fight this war where they're drip fed western weapons and slowly losing ground to Russia every day, if they could do a NATO style combined arms maneuver offensive they would, but they tried that in the summer of 2023 and failed, they don't have the air assets for that and will most likely never get them. Which is why the situation in Ukraine is like this. Ukraine is a unique situation and this does not apply to a hypothetical US-Russia conflict, or a NATO-Russia conflict, or even a US-China conflict, which would be primarily a naval conflict and not a land war. The lesson from Ukraine should be that, it's a unique situation and what's true of Ukraine is not true outside of it. For instance, Shahed/Geran one way attack drones: highly useful vs Ukraine, useless vs Israel.