Too busy having inter isaaq civil wars to think of a strat like that. SL wasn't really a thing until 2001They hade a golden opportunity in the 90s, after things went to shit in the south they could've moved the capital to Hargeisa and cemented themselves as the premier power in Somalia by having RX and Dir at their side while playing off Hawiye and Darood against eachother as neither trusted one another. Though I do think you underestimate how craven the warlords were, they wouldn't do it out of nationalism, they wouldn't do it because in the event one of them succeeded in winning the Civil War they wouldn't want to have ethiopian troops within Somali borders.