Nah. Germany would like nothing better than to keep the status quo and keep buying cheap gas, and Russia falling apart may lead to huge issues with the supply chains of Russian resources. Obviously they can't buy the resources with the war going on, but they may not be able to buy them ever again if Russia falls and turns into Africa 2.0. So the best case scenario for Germany (or at least it seems that's what they are thinking) is ending the war ASAP with a change in Russian leadership, but also letting them save some face.
For USA, it's because of China. China already has huge influence over Russia that will only grow as the West continues to isolate it, but actually breaking Russia's back means it will fall right into China's grasp. If Russia even survived, it would be a glorified vassal to China as opposed to being a player in its own rights (though we already know Russia isn't a first rate player, but it sees itself as such). If it doesn't survive, Siberia will basically be up for grabs and you can be certain China will be there first. They are already there, actually. So if Russia falls apart, you're counting on a small possibility that USA and EU can actually get the new states into their own sphere of influence rather than letting them fall to China.
So there's a lot to lose for the West if Ukraine wins. Obviously from moral standpoint Ukraine has to be supported as much as possible and Russia has to be punished hard, but that's not what politics is about. Just beating Russia isn't hard, either, we all knew it has 0 chance against NATO before the war. The issue is whether Russia can be beat without benefitting China too much, or if there's even a realistic scenario in which China isn't the biggest winner. Point being, at this point Russia isn't really a subject in the eyes of either USA or China, but it's one of the most important objects and possibly one that will decide the power struggle between them in the long run.