What the hell is the purpose of a "protracted cease-fire" that lasts sixty freaking years? This is really no different than a massive public-works project where those who are involved in the design and construction of the project have a vested interest in ensuring that it never gets completed.
Other than protecting millions of innocent people in Seoul from a lunatic with lots of weapons who's eager to kill and overrun them, and containing same lunatic to protect ourselves, I can't think of a single reason. If you're implying that maybe it's time to get on with the battle before it's to late, you might have a point.