Unless the Russian economy collapses first. The ruble has lost 10% of it's value in just the past week. Inflation on many items is near 70% despite interest rates currently being set at 21%. It's spiralling a bit recently due to a renewed wave of sanctions enforcement and tanking petroleum revenues.

Now, that doesn't mean it will collapse, but it does mean they can't keep doing this forever. Number of soldiers available isn't the only factor that decides whether a nation can sustain a war.

Plus their other geopolitical projects are starting to crumble a bit. See: current events in Syria.

I’m out the loop a bit… what’s going on in Syria that would affect the war in Ukraine?