In January 2022, a Canadian expert was unequivocally stating the Russian military buildup on the borders of Ukraine is only posturing. He is still making a good living writing his weekly geopolitical column.

Anyone who claims to know how this history is going to finish is mistaken. There quite a few plausibilities here.

One aspect of this war that supports your hypothesis is that many of the potential soldiers from the ethnic groups and lower-class Russians have been expended in Ukraine. The political forces resisting the Kremlin don't have that cadre of angry young men.