Comment by jefftk

This cites but doesn't link "The Mysterious Case of the Missing Russian Air Force", which is a much more thorough treatment: https://rusi.org/explore-our-research/publications/commentar...

They list three possible explanations:

* Too few precision-guided munitions (PGMs)

* Risk of friendly fire from surface-to-air missiles (SAMs) due to poor coordination

* Lack of experienced Russian pilots