Yes of course, but that is the point. Why do you hit substations when you could permanently destroy the individual targets of that outage?

You do it because targeting the individual sites is not economical. If every 1000 units of currency of range you inflict on your opponent costs you 2000 units of currency, you are basically just hurting yourself.

You target the substation because with one hit you can deny the service on many smaller targets, something which may not be economical if you targeted them one by one.

That means there are targets that would have been attractive targets in a central system, that are no longer attractive in a decentralized one.

Generally centralized systems can be run more efficiently, however it depends since electric transmission is not lossless and the construction/upkeep of the infrastructure is not free. That means the geography of the place plays a huge role. The more spread out the individual sites are, the more a decentralized system makes sense.

Renewable upkeep is a question of the requirements. I know mountain huts in high alpine areas that run on solar for the past two decades and have had basically zero maintenance cost, if you don't count the occasional shoveling of snow. Batteries of course need to be swapped out as well, if you have them, but they can also last a while. But the cost of running centralized power to a single high alpine hut is incomparably higher (if it wasn't, that is what would be there).

Even the big targets nowadays take hundreds of drones launched to destroy, because of air defense. Air defense seems like one of those thigs that's easier to concentrate around a select number of key sites. You won't put a Patriot next to each residential building, but you can put some next to a big power plant.

And the drones today are made with large targets in mind, carrying one bigger payload of explosive. I wonder how they can change if the goal would be to target stacks of fragile solar panelts with best cost efficiency. I've seen on the news yesterday that Russia started targeting bridges more because that have some new payload that's more destructive to them than just a big lump of explosive.

I don't know what's actually true here, just some ideas on what else need to be taken into account.