The Star League warships are interesting for the 'economies' of the Clans . . . basically they are a economic storehouse that is not tapped. They represent several times the GDP of the Clans that own them. Yes, small ships have been made and the very 'wealthy' Bears started to produce two superbattleships, but they did not complete them or build the 3rd until they had a whole Occupation Zone to draw on. A case could also be made that trading their Homeworlds Enclaves is what got them the capital to finish/build the three Leviathans as warships. Otherwise all we see is some building of corvettes, frigates, destroyers and light carriers (York). Not even the Snow Ravens carried out a mass production ship building program, instead they built one offs- which had to hurt them b/c of economy of scale.