His power comes from having his people ADORE him. Thinking he is the ONLY true savior of Russia and Russkie Mir.
In order to keep them subjugated, there is one thing he CANT do....send their 18-20 year old sons to certain death. That is the ONE thing Russians ( especially the mothers ) will not stand for. Sure, you will see a video here, there of a Russian mother "applauding her sons death for the Motherland". But those videos originate in the far east- where they have absolutely nothing in regards to a future ( other than scraping by, working a mine or living off govt subsidy )
Just google "conscription in Russia" and you will find a bevy of information that will give you a better understanding of why Putin has to thread a needle in regards to young Russians- especially those from the Moscow/St Petersburg regions ( Western- more affluent )