I read (sorry dont have a source) that russian fighter pilots fly commercial just to get flight hours, cause they dont get enough from the military. So uh... maybe a lot of them just didnt and maybe still dont have much experience at all. Or maybe they do now... those who still survive.
Any single plane shot down isnt small. And they allegedly shot down 4. Not just that, pilots may also be lost, which is just as if not even worse of a loss for russia.
I recently saw something by Randall Munroe about this, the guy who makes xkcd. Something in there where the moon would partially restart the rotation of earth.