A large number of people signed up for each of those conflicts and where let go. Granted, there were also a large number of conscripts, but even ignoring conscripts they were huge reductions in the government workforce.
Edit: The Works Progress Administration (WPA) is another example which was closed down by Congress and the war boom in 1943 and provided almost 8 million jobs between 1935 and 1943. (http://en.wikipedia.org/wiki/Works_Progress_Administration) After employing 8 million people.
Most of these represented far larger drops in government employment than the end of .Com.