With insufficient cannon fodder, the Orcs' favorite tactic of overwhelming numbers could no longer be deployed. The Five Royal Clans would not dare risk their few remaining people in a life-or-death struggle against us.
Just a few battles would make them realize this, which would lead them into a strategic stalemate.
Although the Elves and the Ancient Races had strong individual combat capabilities, they had ultimately been disconnected from the Continental battlefield for a long time. Both their tactical thinking and their officers' command abilities were severely outdated.
Even with significant military strength, they could at best utilize it to sixty percent of its potential in their hands.
Moreover, both families had limited numbers of people, and could only mobilize a few hundred thousand troops. Even if they were to lose control of the Northern Continent, they wouldn't have the capacity to retain such a large territory.