If those shaheds cost $20,000 which is low balling the cost than that Gepard just eliminated $340,000 worth of drones.
The cost quickly balloons from there for russia as the cost per flying bomb/shahed goes up from having to make them more sophisticated and capable of flying higher to penetrate Ukrainian defenses.
The idea that mass flying bomb attacks are more cost efficient than other types of attacks or that there is no way a defender can’t affordably chew through mass flying bomb attacks with expensive equipment in an affordable way is not really true, under certain conditions it is but under others this is the least efficient strategy possible.
I think a major point here is that mass drone attacks become more viable if your enemy only has expensive means to shoot them down. If your drones are cheaper and easier to produce than the weapons the enemy is using to shoot them down, you are winning in attrition every time the enemy shoots down one of your drones (because, presumably, you can produce more of them for longer than the enemy can produce the counter-measures).
When you take that into account, it changes your equation dramatically: With a 5 % hit rate, you’re spending 1 000 000 USD per target, while the enemy has spent 19 x (cost of shooting down drone) defending that target. If it costs them more than 52 500 USD (on average) to shoot down a drone, you’re both hitting targets, and spending less money doing it than the enemy is spending on defending themselves. A single AMRAAM missile costs around 1 000 000 USD, so if you’re using those to shoot down these drones, you’re spending 20 x as much as your enemy, and still getting hit.
Enter the Gepard (or similar countermeasures). They allow you to shoot down a drone at a fraction of the cost of the drone. You might still be getting hit (around 5 % of the time), but now you’re capable of fielding much more AA at a fraction of the cost. When dealing with these massive drone swarms, volume is the name of the game. A single 1 000 000 USD AMRAAM missile can never take down more than a single drone, so it’s never going to be a long-term viable strategy to use them for drone defence. It’s much more reasonable to field a truckload of Gepards (or similar) so that you have enough volume of fire to take down all the drones headed your way.
I think we/I have some confusion about which cost effectiveness we’re talking about. Your comment is about the cost effectiveness of (Ukraine’s) drone defense, where the defense costs are lower than the attack costs. Ukraine is doing really well on that front to the point that they’re selling tech to other countries.
My comment was about the viability/cost effectiveness of Russian drone launches. For that calculation they need a drone launch price < target value + air defense cost. Since targets tend to be quite valuable, it’s not too hard to make it cost effective, although not necessarily more cost effective than other means.