Quick answer? They don't.
They were losing the war horribly, the only reason they managed to survive in all actuality was because Fereldan took them in and despite the Templars themselves being a professional army, they didn't have the numbers or backing to invade a sovereign nation. So things devolved into a stalemate, but in truth? The state of Thedas will tell you all you need to know about this.
They were decimated across its bounds, in a constant stream of retreats and ambushes from Rivain to Orlais itself, by the end of the engagement pre Conclave? The Mage Rebellion, which had effectively been more or less begun by all circles, was effectively restricted to two areas of operation, Fereldan's Redcliffe and Fereldan's Northern Forests near Amaranthine, a rebellion of thousands, now a rebellion of hundreds.
I just wish we got to see the slaughter personally, I mean seriously, the Mages were asking for this war for a decade and they finally got it.