I wrote about this early in the conflict too (not that what I write means anything). In short, I argued that an Air Force is the least susceptible to political pressure and agendas. Remember when Erdogan threw many of his air force in near jail. He walked that back soon enough.

You seldom see some air force guy in a war movie saying, "I'll volunteer for this suicide mission." They don't take unnecessary risks. You can't work in aeronautics with a cavalier attitude towards all risks, large and small.

No one in the FSB can operate that equipment. They can't say, "do this or I'll get someone who will." Helicopters slightly another story. Controlled by an Army, Putin has some control.

Also, Putin understands that without the threat of the air force Russia is done. So the combined factors of, he orders and they ignore, with his not wanting to risk losing it all, have kept Russia air force sidelined and I doubt that will change.

The U.S. understands this and is playing the waiting game. That's the irony of all this. Putin believes he will win the waiting game. If he kills enough villagers the West will back down. Irony because he believe the West believes its own "rights of humans" bs. Putin doesn't know the definition of cruelty. Sadly.