The argument is literally that it is problematic to send 100 k$ interceptors to stop 1 k$ drones and then you turn about and argue you can end 100 k$ cruise missiles to stop 1 k$ turrets. Your argument is inconsistent with the entire premise.

You have presented no evidence as to the overall cost of this mystical unstoppable drone swarm. In contrast, we do know that shotguns, machine guns, and bullets are cheap, mass-produced, and mass-deployed by the tens of millions.

The key unknown of my proposal is the bulk cost and production of a small automated turret or fighter drone that can economically and flexibly deploy cheap bullet interceptors to asymmetrically defeat expensive drones. However, the operational requirements for such devices are simple and within the range of existing technology.

There is no clear evidence that cheap explosive drone swarms are magically cheaper than cheap fighter drone swarms or cheap ground drone swarms. It could easily go either way and without a rigorous actual analysis you and I are both unqualified to determine what is actually dominant.