This is a ludicrous claim. The movie wouldn't have made as much as it did if it didn't pull in entire families by the bus load. It also pulled in more families than every single Potter movie individually. Logic fail.
Just because a movie was high grossing, doesn't mean it was drawing the whole family. Titanic was number one (not adjusted for inflation) but I doubt that was a big family draw, it's money came for a high level of repeat customers. And what about Dark Knight at number four? There's a family friendly movie for you.
By it's second theatrical run, I'm pretty sure everyone know Star Wars is here to stay. Avatar did the same with its initial run. The buzz about these sequels today is massive. The film also got good ratings from critics and audiences. They liked the story and characters.
I disagree with this. A year after Star Wars came out you could probably go up to almost anyone on the street, say the name of one of the lead characters and most people would probably know who you were talking about. As for Avatar, don't get me wrong I really liked the movie, I doubt you could find to many people who really remember the characters, even amongst people who saw it. I just didn't seem to enter the cultural consciousness like Star Wars and Harry Potter did. Maybe that will change with the more movies, but that is yet to be seen.
I also don't see massive buzz about the sequels. Checking Google news, there are 62 articles today about the Avatar sequels. Picking a random piece of entertainment news to compare with, a casting rumor for the next Hunger Games movie, 104 articles. Not scientific, but if the buzz was massive I would expect more media coverage.