As far as I know, the peace between North Korea and South Korea is only base on a ceasefire agreement rather than a full peace treaty, so what was the reason things were left in this situation for seven decades? Is it likely they will even bother to sign an official peace treaty some time or is the current ceasefire a de facto peace treaty?
I don't think they ever truly ended the war. They are no longer fighting, but they did not come to true peace. There has always been some sort of tension between them ever since I think.
One reason why there is no peace between the Koreas (Coreas) is that it is not in the interest, or the preceived interest, in the dynasty ruling either nation. Certainly this is evident in the North where one family has ruled. They use the tension of the conflict to justify their control. In the South the picture is much more murky. The South's president at the time of the outbreak of the conflict was Sygmond Rhee. He had recently been voted out of office, if I am not mistaken, but used the crisis of the conflict to justify his administration remaining in office, at least to the end of the war. But if the war never ends...?
Maybe they just felt the cease fire was good enough. After all this time, the cease fire has been working, so if it ain't broke, don't fix it.
In my opinion, both sides still have the same end goal of absorbing the other side into a single Korea. At the end of Korean War, they had been fighting for around 3 years. A ceasefire was needed to recover their military/economy. Neither side has given up the idea of fighting again, but they just won't directly say it. So a ceasefire was good enough for the time being until they feel comfortable to fight again. Although neither side expected the recovery took so long, but they time they realized it... it was too late to resume the fight compare to in the middle of the Korean War. Just ask any Korea if they'd give up the idea of a united Korea. I don't think you will get many "no".
