The OT crowd like us, or I guess fans who grew up in the 80's who made SW what it was revered those 3 movies. It wasn't just the fact that I enjoyed the movies, cause I enjoy alot of movies, it was that they were my favorite set of movies of all-time, and that is a big difference than just being a fan.
I love Back to the Future, Superman, Terminator, and many other movies of the SW genre growing up, but nothing, I mean nothing compared to the OT movies, and that is what Lucas doesn't understand, SW is a religion to me, not just some movie I enjoy. I see my nephews really enjoy SW movies, but I don't think they have that love for them that I did growing up. I don't see them running out when their older and buying every release that hits the shelves.
The big thing about just being an OT fan, that is different than being a saga fan, is the OT movies as individual movies are great, and that is what drives me to watch them over and over. I know so many PT fans I talked to on TFn say that ROTS is the only great PT movie, and TPM & AOTC have their flaws, but they still enjoy them. I would ask anyone, I enjoy alot of movies, but you have to love something to want to watch a movie 20 years later.
SW & ESB are classic movies in a quality sense, not in a SW sense, and because they are so great, I cut ROTJ slack, and I can watch those 3 movies in order without ever hesitating. With the PT, it is a chore, I used to try to watch it 1-6 because it felt like an obligation to watch the whole story, when I lost site of with the OT, I watched the story cause I loved the movies, now I watch the movies out of obligation to the story, and that doesn't bode well for 1-6 for many fans in the future.
As I said, I think there will be 1-6 diehards 20 years from now, but that group will be nowhere as big as the 4-6 OT fans since 1977, cause the quality of movies in the PT just aren't there for longevity, plain & simple. The fact that my 8 year old nephew already thinks Jar Jar is stupid, when he liked him 4 years ago, tells me he isn't going to be religiously watching TPM when he is in his 30's, the same way I watch the OT nowadays.