My take is Russia didn't believe Ukraine has enough capable drones to impact oil infrastructure. Despite all the rah-rah news, I'm not convinced Ukraine can significantly hurt Russian infrastructure, with destruction alone.

I believe, or hope, the strategy is more nuanced. The biggest two problems Russia faces with oil infrastructure is 1. the removal of Western parts and knowledge. 2. the reduced number of young Russians capable of running the equipment. And a 3rd problem, unrelated, but important, a global economy going into a recession reducing the demand for natural resources.

A few years ago, a drone hits on equipment would be quickly fixed. Today, Russia may experience what the U-boat experienced in "Das Boot" (a movie you're probably too young to have seen). In the end, the captain wails something like, we lost for the lack of 2-pfennings worth of copper wire.

So I'm making the for want of a horseshoe analogy.

That's what I believe Ukraine is trying to do to Russia with this far-flung attacks. It's an attack on their economy, as you point out too.