Can we just stop with the nuclear strike silliness already? That’s a complete no-go for too many reason to be worth listing.
The two critical factors holding Russia back from a much more extensive strategic deep strike campaign are: ISR, and PR. With munitions supply an additional half factor.
The foundational core reason why Ukraine has been able to punch way above its weight in terms of hitting high profit targets in Crimea has been NATO ISR. You have US global hawks preceding every Ukrainian strike sitting impossibly close to the action and providing live updates to co-operate Ukrainian assets to penetrate Russian air defences.
This is an ‘impossible’ scenario that no AD network can counter because there is no way in hell NATO assets would be able to maintain such close and uninterrupted view of the battlespace even if NATO was directly involved in the war. And if the positions were reversed, NATO would have declared any Russian assets so blatantly involved in the kill chain as legitimate targets and killed them in lawful self defence. This is an uniquely stupid position the Russians have managed to trap themselves in that no one (well, no other major power) else will tolerate and allow.
What the Russians are facing is instead what would be the norm one would expect in near-peer conflicts. Where you have sufficient strike power to be able to punch through enemy AD networks and hit basically most targets you want, but lack the frontline ISR assets to be able to find time critical targets and also have very limited post-strike BDA capabilities.
While the Russians can go scorched earth, especially in winter, to take down Ukraine’s power grid for example, what actual military objective will that really achieve for them? Ukrainian industry is dead, they are not making any material contributions to the war effort, pretty much all war materials, weapons and supplies are coming in from abroad.
All they will achieve with such a move is purposely create a massive humanitarian disaster, and plainly for no good (military) reason.
While the US and NATO countries certainly couldn’t be much more anti-Russian, most of the world is actually still neutral, especially the global south. That is why the Russians cannot afford to not consider the PR consequences of their actions.
Lastly, while the Russians are by no means running out of missiles as the western MSM keep wishing out loud, their missile stocks are not infinite either. And a sustained national strike campaign to take down and keep down the Ukrainian grid over a meaningful period of time, will certainly put a sizeable dint in their missile stocks. Given the above points about the irrelevance of Ukrainian industrial contributions to their war effort, as well as the obvious PR and diplomatic costs, its little wonder the Russians have concluded that it makes no sense for them to mount this kind of purely spiteful campaign.
And let’s not be disingenuous and think last winter’s power grid strikes were really seriously about trying to collapse the Ukrainian grid. That strike campaign was primarily aimed to forcing Ukraine to re-deploy and spread out their air defence assets to take the pressure off the VKS on the frontlines, as they were suffering a decent and growing amount of combat losses up to that point. A situation that was almost completely reversed following the strikes and subsequent Ukrainian AD redeployments, which justified that strike campaign.
The highest impact investment the Russians can make to allow them to get more out of their missile deep strikes are space based ISR assets. It will be interesting to see if they can manage it. Because unless and until they get a quantum leap in space based ISR assets, their current deep strike results are about as good as could reasonably be expected.