A carrier group will bunch together for a photex, but when deployed they spread out over many square miles to sanitize the area around the carrier. Point defence systems like Sea Sparrow protect their parent ship for several miles, and area defence systems like Aegis/Standard SAMs cover the group out to 50+ miles. Consequently there is no need to keep those ships within spitting distance of the carrier. Also, if an enemy attacks with nuclear weapons, by spreading the group out it becomes impossible to take them all out with a single strike.