Bigger variety of interception methods from the Russian side that run the gamut of costs. They never stopped investing in things like mobile, self-contained SHORADS like the Pantsir or Tor nor they never got fully rid of tubed AA.why has missile and drone interception been a thing in the ukraine for so long despite the economics being lopsided as anywhere else and russia being able to overload them as with that one time with a few hundred gerans in kyiv? just more arcane political calculations on the russian side?
The west became so reliant on air power that SHORAD fell to the wayside until recently, relying mostly on the nth Stinger variant(or other MANPAD derivatives) which isn't particularly good anymore or expensive repurposed AA missiles that makes mass fielding of them financially difficult and hard to replace once spent.