Frankly, all of the top 10 adjusted for inflation had huge numbers seeing it more than once. Several had more than one theatrical release. Avatar, with only one theatrical release and a very limited adjustment for inflation, grossed an obscene amount of money. People can talk it down all they want, point to 3d, point to whatever they want, but all the highest grossing films of all time have some kind of hook that differentiated them.
Gone with the Wind had revolutionary set pieces. Star Wars, E.T. and Jaws had ridiculous special effects at the time of their release. Titanic had an almost full-scale half model of the ship mechanically sunk for a scene. Snow White and the Seven Dwarfs were a huge step forward in animation. The only movies on the inflation adjusted list that were primarily story driven as opposed to groundbreaking filmmaking in some way were The Sound of Music, The Ten Commandments, and Doctor Zhivago.... All of those pre-1966.
Further, the way Avatar stood out in 2009, in a time of way more studio releases than existed in the 50s, 60s, 70s, and 80s, makes it that much more impressive. The top grossing movies before and after Avatar made less than half the gross of Avatar. The next movie to make more than 2/3rds as much as Avatar was The Force Awakens. Frozen, for example, as big a hit as it is for Disney, grossed significantly less than 1/2 as much.
There is no way to wish away how big a hit Avatar was in 2009. On a historical basis, it was a massively popular movie.
