If you are right about Russia losing the war of attrition (I am not certain, though I certainly hope so), this will result in some internal unrest. The Muslim part of the Caucasus may well secede, places like Dagestan have negligible ethnic Russian population anyway. The next leader will have a lot of work on his hands just to keep the federation intact and Russian politics at least a bit independent on China.

Ultimately, a younger Russian leader who does not live in the past like Putin does may realize that Russia now has fewer people than Bangladesh or Indonesia and cannot afford old-style wars of conquest anymore.