Interesting: I always thought that the delay was just something I kept running into, because I took three history courses in middle school/high school (the effects of moving through three states between 1978 and 1980) that always stopped at the same point. In my case, though, I was always amazed that American History classes ended with the end of World War II, with no discussion of the Marshall Plan or Korea, and definitely not a mention of my most burning question at the time: "Just why the hell did we go to Vietnam?"