It's a lose/lose situation for Putin. If he wins the war, the Russian economy will be in ruins for years if not more than a decade and they'll be faced with rebuilding Ukraine.
If he backs out now he loses face, loses Ukraine, loses the support of the Russian people when they discover the level of carnage and over 12,000 dead soldiers. Apparently demoralised Russians are deserting in droves, and those that surrender are begging not to be sent back because they'll be off to the gulag.
