It also seems like a bit of a game of whack-a-mole. UA put logistics/distribution centers under threat (wildberries) and refineries under threat, so the Russians moved their scarce air defense resources around on the map in an attempt to cover those, but oops, that left little or nothing covering the yandex datacenters and similar. There's not enough to go around to cover all of the possible geographically distributed pain points in the economy.
First, a long-running SEAD / DEAD campaign by Ukraine last year and early this which thinned Russian air defence throughout occupied territories and left Russia with difficult deployment decisions for what remained.
Second, improvements to drones (speed and EW resistance) and expanded production - meaning the air defence can be saturated.
Third, Russia's vast geography itself, leaving countless approaches to targets impossible to defend.
A mystery really...
First, a long-running SEAD / DEAD campaign by Ukraine last year and early this which thinned Russian air defence throughout occupied territories and left Russia with difficult deployment decisions for what remained.
Second, improvements to drones (speed and EW resistance) and expanded production - meaning the air defence can be saturated.
Third, Russia's vast geography itself, leaving countless approaches to targets impossible to defend.