I think the difference is that the Russians still have a significant fixed and rotary wing strike force. They’re not flying as much right now because of the anti-air, but also because the war is static. If the Ukrainians were to begin marshaling men & supplies for an offensive that would be different — that would be presenting targets worth the risk.
That’s a good point. One reason the war is static is that each side has defensible lines.
The Ukrainian SAMs that are keeping the Russian planes on the ground are embedded in forest and urban areas. They become much more vulnerable if they have to support and advance through the open fields in the south.