Artillery shells have a long way to catch up to the Russian production levels but combined NATO production should be close to the Russian level. This is also proof that air-defense missiles can't win the war in the long run against cruise and ballistic missiles. 500 Patriot PAC-3 is not enough. Russian total cruise and ballistic missile production should be at least double that amount. Chinese have automated factories to produce cruise missiles. I wouldn't be surprised if the Chinese can produce a thousand cruise missiles per month. It is a lost cause.
A couple things I disagree with here.
1. The West doesn't have to match Russia's production of 155mm artillery shells. In fact, they don't really have to even come close. What they do need to reach is a level in which Ukraine can fire 3000'ish 155mm shells per day, supplemented by 105mm, 122mm and 152mm artillery shells. 155mm shells and the systems that fire them (M109, M777, Panzerhaubitze 2000, CAESAR, Archer, etc) are of higher quality, greater range and better accuracy than the overwhelming majority of the Russian systems they oppose. What Ukraine needs is a steady flow of domestically built Bohdanas, supplemented by the various Western systems. That will be enough to hammer Russian armor as advances and significantly outrange most of Russia's systems.
2. People misunderstand what PAC 2 and PAC 3 Patriot missiles are actually use for. Along with ASTER 30 missiles fired by the tier 1 SAMP-T systems donated by France and Italy, Patriot missiles are saved to intercept Russian balistic missiles that other systems can't handle. Specifically, they are used near Kyiv, Lviv and Kharkiv and important Ukrainian military installations. Patriot missiles are not fired unless Ukraine is trying to intercept Iskanders, Kinhzals or the odd cruise missile that slips through the layers of other systems. For that reason, Ukraine doesn't need thousands of PAC 2, PAC 3 and ASTER 30 missiles per year. They need enough to ensure that their key cities and military facilities are well protected from balistic missiles strikes.
Shahed drones and Russian cruise missiles can be handled by a combination of multiple systems. IRIS-T, NASAMS, HAWK, Gepard, Crotale, FrankenSAM (RIM-7), Martlett, Avenger (Stinger), Vampire and even Soviet systems such as BUK, KUB, Strela-10 etc. Those systems can be further helped by the MiG-29s, SU-27s and F-16s flying air cover and operating as airborne air defense... What most people don't realize is that the majority of IRIS-T, NASAMS, etc have not even arrived in Ukraine yet. Their air defense is only going to stiffen in 2025 and beyond. Patriot is only part of that equation. There are much more cost effective systems for intercepting the majority of Russia's projectiles than Patriot. That said, USA
isn't the only one building them. PAC 2 GEM-T are built in Germany
as well and Mitsubishi is going to build them under license in Japan
.
Air defense is just one part of the process. The destruction of Russian launch sites near the border will help Ukraine create greater buffer zones.