And actually in Sins of a Solar Empire, nearly every ship avalable is a capital ship. Fighters can only be built in small squads in that game, and are typically only used in defense....though the could be deployed on carriers
Basically.... SoSE is about cap ships, not nessisarily every other game
Homeworld is a better analogy I think. You can build fighters, corvettes, frigates, etc. And you can win with only fighters, but it takes some skill and luck. But you would want to send a capital ship into the bigger fights as a heavy hitter and a bullet magnet:P
