I'm not sure that the current situation could be characterized as one overarching war, but a whole series of smaller, relatively lower-intensity wars going on all at the same time (The FWL reunion tour, the brushfires in the Hinterlands, the Suns kicking the Kurita squatters off of their territory, the big Ghost Bear kerfluffle, the Canopians finally laying the smack down on those Roman cosplay posers, and Wolves vs pretty much everybody), kinda like what you had with the Third Succession War as opposed to the massive conflagration of the First.
Or to put it in historic terms, it's more like the sporadic discrete wars in the 18th century between France and England that some liken to a proto-World War -- Queen Anne's War, the Seven Years' War, the French and Indian war, the American Revolution, etc. -- than it is the Thirty Years' War or the total war against Napoleon.
So it may be that there is no "expiration date" to the current state of war, because the fighting is of such relatively low intensity that the various combatants aren't going to quicky "tire" of it. Certainly the House Lords by and large aren't going to worry about public opinion and anti-war sentiment (particularly Kurita and Liao) if such exists, and the industrial and military bases may be able to make good losses.
And let's face it, from a meta perspective, it wouldn't be profitable for Catalyst if a pandemic of peace were to break out across the Inner Sphere
