I disagree: lots of cheap drones would be extremely effective against an aircraft carrier. They don't need to sink the ship; they just need to damage the jets or disrupt operations on the flight deck. Even a small drone is a serious threat to a jet. How can a carrier defend against a drone swarm? They only have so much ammunition for those CWIS guns, and defending against the swarm will probably cost a lot more than the swarm itself does.

Of course, this assumes the carrier is within range of the drone swarm, but that seems to be the assumption in this line of argument.

Eventually, I think they'll have more cost-effective defenses against small, cheap drones, but they don't have them yet.