Scarcity is not some kind of minor detail; it's damned near the whole story. Logistics win wars. Scarce weapons usually lose wars against abundant weapons. That doesn't always happen—the Zulus' abundant spears and arrows were no match for the Maxim gun's somewhat less abundant cartridges, and neither a pitchfork nor a handgun will do you much good against a tank—but it does usually happen.

When scarce weapons can defeat abundant weapons, and it's not because of range, it's usually because of precision. Drones are great at precision. 3 mortar rounds falling within 30 meters of your target trench are still ten times less deadly than a single FPV drone you can pilot straight into it.