But how many can they knock out? Patriot air defenses are extremely effective. But on some level they’re not very useful if the interceptor missiles are materially more expensive than the things they’re intercepting against a foe of equalish economic means.

“Drone” covers many orders of magnitude in capability, but a CIWS can handle functionally unlimited numbers of the low-end, and the high-end don't clearly win the cost-per-kill war.

Drones are game changing on land because they allow smart munitions to be usefully spread across an entire country, far outpacing a defender's ability to deploy air defenses. But a carrier battle group doesn't have this problem: the defenses are necessarily already positioned on and around the thing being defended.

Where the cost balance starts becoming relevant is when destroyers are trying to defend other vessels: something that could be easily shot down by a CIWS at the target might require an SM-1 if the Standard is coming from 100km away from the target vessel.

I don’t think it’s clear at all that a CIWS system beats a large swarm of jet turbine drones. I think Ukrainian sea baby style attacks are also going to be very tricky if scaled up beyond the levels we have seen in this war.

FPV drones, imo, have created a system of dynamic mines, effectively. Both sides are able to project defenses forward without boots on the ground. I suspect this will revolutionize naval warfare shortly on a similar kind of story. If it ever becomes relevant again.

““Drone” covers many orders of magnitude in capability”

I don’t know why you’re repeating that. Drones are a growing class, but I have specified several specific archetypes and drones all generally share the same basic advantage which is that they’re much cheaper than historical alternatives.

If you’re just trying to say that there are some drones which won’t be effective against ships that’s just kind of silly. Obviously that’s true.