Everytime I read an article about how great the Dark Knight is doing at the box office, it is followed by a disclaimer. Because of inflation, not nearly as many tickets are being sold. It would have to do over 900 billion to beat Titanic, and 1.2 billion to beat Star Wars.
What does nobody mention? How 'bout the fact that there were so fewer alternative forms of entertainment when both of those movies came out? Cable TV, the Internet, Video games - these didn't exist for Star Wars, and were not nearly as advanced or addictive in the late 90s. Not to mention no one thought they'd be able to see Star Wars at home on DVD within 6 months of its release. We just prayed the commercials would cut out too much with the Network Light Sabres once it came on TV.
The Dark Knight may not be the biggest movie in history. So what? It's still amazing that a 70 year old comic book hero can take over the world for a month.
