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.