Welcome to the jeune ecole. The problem of $1000 drones is range and speed. A carrier is moving at 20kt, regularly. More if conducting flight operations. $1k drones are group 1 drones in DoD classification. There are limited in speed and range. If they teleported into range of the carrier, sure, they could reach it, and keep up with it. But if they don’t start near the carrier, how close do they need to start to do so?

To get holes at the water line, you’re going to have to take your drone down to the water line. Which means you’re going to have to deal with the waves and spray from being down there. Cheap drones are not notable for dealing well with hitting the water.

Beyond the thick steel plating, and compartmentalization, there’s also the fact that little holes just won’t let in much water. If you want to sink a ship, you need to let in more water than the pumps can take out.

If you start talking about $50k drones, then a bunch of these objections start changing. You can get much more range, much more speed, much larger warheads, and much greater capabilities in general. But your cost curve has changed a bunch, so you get 200 drones instead of 10k drones for a given amount of cash.