Here's my pet theory: when I try to put myself into an average high school student's shoes, they're already surrounded by all the CS achievements today; namely, video games and smartphones and Facebooks. They're exposed to them a bit too much. On the other hand, when I was a high school kid I didn't realize how CS is affecting our infrastructure and how many things are still unsolved. I guess this still applies to the current generation too. Combining these two, the field might look rather "finished" or "too competitive" to an average person, which could deter them from applying.
