I don’t think that this is a realistic scenario right now. What is even the probability of a real “toppling” of the Russian state in the current situation? That would pretty much need a full invasion and occupation by western forces or a true proletarian revolution.
I think it would be more likely for some sort of western-led color revolution to occur and in the light of a color revolution it’s just not sensible to talk about revolutionary defeatism, since all the systems of a bourgeois state would already be in place. The means of production are either part of state-owned firms or firmly in the hands of the Russian bourgeoisie. It certainly wouldn’t be anything like the “shock therapy” after the fall of the USSR. The state would stay the same, its class character unchanged, just with different capitalist factions with different interests in power. It would lead to more capital movement from the west into Russia, state firms would get privatized, profits moved out of the country. For the Russian working class it would worsen all the effects of capitalism. Funnily enough it would probably be a lot like what has happened to the Ukraine. It would be the regular mundane evil of the current imperialist world system.
All in all I don’t think that the current situation actually strengthens the position of the Russian working class in their class struggle. The Russian state has only become more repressive during this war. Additionally, a strong, independent Russian economy with a big public sector will potentially ease the contradictions of capitalism and thus placate and capture the working class (cf the history of western European social democracies).
See, the thing is, I can certainly turn the tables on this and ask you if your post is in good faith. Because let’s face the facts, this is a textbook imperialist conflict. It doesn’t matter one bit if Russia’s doesn’t meet every criterion for being an imperialist hegemon right now. Imperialism is capitalism in decay and every sufficiently developed capitalist state will turn outwards to become imperialist eventually. What’s actually important is the class character of the states or blocs involved and Russia is a bourgeois state that exploits and represses its working class. This conflict has done nothing so far to strengthen the positions of either the Ukrainian or Russian working class in their class struggle and neither side represents actual liberation from the capitalist hegemony.
I agree that this situation has been a blow to the US-led western hegemony and that these are certainly interesting times with a new multi-polar world order appearing… But I fear this is just the prelude to a bigger conflict on the horizon where the actual consequences for the international class struggle are not foreseeable.