Their economy is in a terrible spot because of the war. International sanctions mean Russia has extreme trouble selling its natural resources or importing necessary products, and what trade it can do it pays a stiff premium for. Its massive defense spending might appear to boost GDP but it's all unproductive and it's driving massive inflation. Then you got oil refineries and other such infrastructure periodically exploding. And true end to the war means an end to all those problems and is the only way for them to avoid their economy collapsing. Of course at the end they'll need to be careful about how they draw down defense spending to avoid recession but they'ed at least be in the drivers seat, as opposed to what they are looking at should the war continue for another 1 to 2 years.