Ukraine

Russia is all in. Europe is sending surpluses and old stuff, which is not much, because we have small militaries. The US has a fuckton of hardware but also sends very little because putler is balls deep in one of their two parties.

Russian economy all in versus Europe's scraps plus a tiny bit of what the US has is approximately balanced.

Ukraine is not NATO, so helping them is not mandatory. European countries all have shit going on because of the last few crises, so as long as Russia is not at our actual border, we don't care enough to commit 100% and deal with the damage that would do to our economies. We must tread lightly as we basically already are US vassals and we don't want to give up more autonomy, and we don't want to risk losing more influence than we already are to China. US has their own shit going on, and Turkey is now probably more aligned with Russia than with the rest of NATO.

So, essentially, no one cares enough to commit more. If NATO countries REALLY cared about Ukraine, the Russians would be out of the country already.

Putin is more willing to sacrifice his own people and leech every single resource in the country (which he basically controls, making him the ACTUAL richest man in the world) to support the war effort and there's no war crime he won't commit, with the possible exception of using nukes.

Plus, like Nazi Germany leading up to WWII, Russia has probably been fortifying their military much more than richer countries and Ukraine in the last few decades.

Or to put it in animal terms: Ukraine is a plucky terrier, the West is a German shepherd, and Russia is a rabid wolverine on steroids and bath salts.