SPATR and Mongols have the cash and desire to fight, so they continue to fight. If their will to fight outlasts their opponents will tofight, than they will gain more favorable terms. Though just admitting defeat isn't that bad of a term, I come from an era of "draconian reps" and harsh terms. Now anything more than a white peace with an admission of defeat is considered too harsh. Regardin this war, theres not much less lenient terms that can be made, but war will continue until both sides agree to peace.