Commissario
YupAlso US ships don't sail alone as seems to be common for Russian ships. They sail in combined groups, which makes picking one off much harder for the enemy and much easier to defend. When Russia lost its flagship Moskva, she was sitting off the Ukranian coast all alone and it took hours for backup to arrive. The US strategy is one learned in WW2, where German subs would find it easy to destroy lone ships in the middle of nowhere but when ships grouped up and defended eachother, the Germans found it much harder to attack and 75% of German submarine crews ended up dying for it
Basically if it's a ship on it's own it's only got the resources on board (including the crew) to deal with everything at once, including full 360 watch and cover which is incredibly hard, especially over a longer period of time as you can't have the crew resting as normal or doing a lot of maintenance without your ability to protect yourself affected.
A group of ships working together have far more redundancy and duplication in their protective abilities as they'll be able to have overlapping watches of the same area and overlapping coverage for their protective weapon systems so something like a torpedo or a small boat lying low in the water that might be missed (both by the watch and weapons) of one boat is far more likely to be seen and be able to be engaged by another.
You also have the ability to have ships designed specifically to excel in one role such as anti sub/anti air protecting the larger ones that might have some capacity for that, but are really meant to be doing something else.
I can quite see the likes of the current ships that are used as part of the missile defence role getting new equipment or updates to improve their ability to deal with smaller targets as they're already designed to spot small, hard to detect fast moving objects such as see skimming missiles, so potentially additional fast firing small calibre weapons could be the cheap and effective way to deal with a lot of the drones rather than relying on large anti missile/anti air weapons (which you run out of fast).
I can think of a a few ways that potentially something like a frigate could possibly improve it's ability to detect incoming drones involving taking ideas from WW1 and 2 and updating them with modern tech, and do so without making the ship itself an easier target for anti radar missiles.