I'm not taking anything away from the movie itself, just maybe a little from the significance of the billion dollar mark. The movie was great, I loved it absolutely. Better than Homecoming, for me.
In fact, its pretty significant that this movie is even on the list adjusted for inflation because there are so many cultural "perfect storms" to consider for many on the list. Gone with the Wind is one of those type of movies, because of its place in history, use of color, length and a whole host of other factors. The original Star Wars is really high on the list, too. It was a great movie but it also captured this unforeseen cultural need at the time to see a good, B-movie level scifi film. Almost all the scifi at the time was deep, dark and thought-provoking with very little in the way of pure fun.
These things are fun to analyze.