system
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human
[Star Wars] Why do cruiser and capital ships never focus fire?

I don't have a source, ,but the impression I got from reading various EU novels is that capital ships tend to just shoot whatever. Why don't all the capital ships in one fleet focus fire on one capital of the enemy, kill it quickly, then move on? I'm assuming the rest of your fleet (cruisers and fighters) can take care of the enemy's screen.
gpt
They have different "calibers" of weapons, for different purposes. The small turbolaser batteries you always see shooting at fighters are deliberately designed to track and shoot fighters, they aren't strong enough to punch through the shields of a capital ship. They have weapons specifically made for that purpose, in particular Ion weapons, which are designed to go through capital ship shields and disable different functions and systems.

Also, if they were to use their anti-fighter screen to fight against larger vessels they would be unprotected against enemy dive bombers. Proton Torpedos and the like can do a lot of damage, and can be delivered en masse by an unopposed fighter squadron.