Yeah, I think it was mostly the 3D hype (and great marketing) that made Avatar a success. The movie itself is more or less just the sci-fi version of Pocahontas.
When Films&Stuff on Youtube did a 10-years-later video on Avatar [1], they said that it was not just about "the 3D hype". It was that Avatar was the first (and maybe still only) movie to use 3D effectively because they emphasized Positive Space (creating depth through 3D to strengthen immersion) over Negative Space (the popping-out-of-the-screen effect that's more commonly used because it's way more noticeable, but also gets old fast because it's fundamentally a gimmick).
I too have quickly grown tired of 3D movies and actively avoided them for the last 10 years, but when Avatar 2 comes out, I will definitely see it in 3D.
