There are a lot of reasons why the emotional half-life of 9/11 has been so short, many of them good, or at least understandable. We haven’t been (successfully) attacked at home since 9/11, for example.
But it’s important to remember that from the outset, the media took it as their sworn duty to keep Americans from getting too riled up about 9/11. I wrote a column about it back in March of 2002. Back then the news networks especially saw it as imperative that we not let our outrage get out of hand. I can understand the sentiment, but it’s worth noting that such sentiments vanished entirely during hurricane Katrina. After 9/11, the press withheld objectively accurate and factual images from the public, lest the rubes get too riled up. After Katrina, the press endlessly recycled inaccurate and exaggerated information in order to keep everyone upset. The difference speaks volumes.