There is an assumption here that the value in improving defenses is the same as improving offensive weapons. That is not the case in the assymetry that drones provide and Russia is the first example.
Russia has not been able to improve AA capabilities to the point where it's "safe", for any definition of the word, neither has Israel. Israel and Gulf states often tout over 90% interception rate yet it's really at the mercy of Iran to not target their most vulnerable sites. If Iran was routinely targeting desalination plants and refineries it wouldn't matter if it was 99%: one hit is all it takes. Similarly Russia cannot keep Ukraine from targeting their oil infrastructure.
Air defenses need to be 100% to prevent physical, economic and moral damage. That is an impossibility.
Russia has not been able to improve AA capabilities to the point where it's "safe", for any definition of the word, neither has Israel. Israel and Gulf states often tout over 90% interception rate yet it's really at the mercy of Iran to not target their most vulnerable sites. If Iran was routinely targeting desalination plants and refineries it wouldn't matter if it was 99%: one hit is all it takes. Similarly Russia cannot keep Ukraine from targeting their oil infrastructure.
Air defenses need to be 100% to prevent physical, economic and moral damage. That is an impossibility.