I'd recommend waiting more than a mere 9 hours for a question like this. Also, in EB outliving a faction could mean your in for the long haul unless you actively destroy it. In which case choose a weaker faction and just for that. Baktria has relatively small victory conditions and to destroy/outlive a few factions. You could always just decide your own victory conditions and play the long term campaign. You won't get a special message, but you will have achieved your goal.