By 1955, the US government had in large part determined it could never recover the lost men. “The problem becomes almost a philosophical one," concluded a then-classified 1955 Pentagon memo. "If we are ‘at war,’ cold, hot or otherwise, casualties and losses must be expected and perhaps we must learn to live with this sort of thing. If we are in for fifty years of peripheral ‘fire fights’ we may be forced to adopt a rather cynical attitude on this (the POWs) for the political reasons.”
Today's Pentagon POW/MIA effort focuses mostly on recovering remains of those known killed since WWII, an important task it does well. This involves determining where to look for the remains of missing (almost always those our former enemies claim were killed in battle during the war) and then recovering and identifying them.
There is no appetite for a relentless effort to trace those men known to have been kept after Korea. The Pentagon can expect no real help from the Russians, Chinese and North Koreans. And there is no pressure from the White House or Congress.
Imagine what the American leaders of 1953, not to mention the prisoners and their families, would think, especially given the cordial relations America has granted Beijing and Moscow, and the very food to keep alive many North Koreans, without ever requiring the truth about our lost heroes.