It goes to the very roots of Indian culture. It highlights most importantly that we respect our elders. This plus the wonderful music and the whole treatment. That's what made DDLJ a cult film. It became more so overseas because the characters in the film were ones based overseas who come to India to find their roots.
Nobody plans a movie to be the greatest.
It becomes great. Even today audiences like it. We don't know how long it will run. I think the main reason was the story and the fact that it helped people find their roots in our culture. I remembered the day I heard the subject, a year before he started the film.