Classical Indian music is based on ragas (motives or melodies). However, a piece of music can last for hours with a skilled musician subtly developing the raga from one to state to another. If the raga (or melody) never changed, it wouldn't be long before the piece would become monotonous and boring. However, because the raga is changing, developing, moving as the piece progresses, there is a sense of interest in the music - and yet, the melody (raga) is still the key element to the music.
In an article by Anil Srinivasan of The Indian Times, he discusses the use of classical Indian music in films. "Film songs, especially the melody-intensive ones, have a pleasing effect on the ear (karnatak). These numbers usually have a classical base, employing ragas effec-tively in a manner that makes you move to the lyric. The lyrics themselves are usually simple and effective, and manage to communicate effortlessly. In so doing, they place the listener in a soft spot a room where the story, the melody behind it, the harmony that underpins it and the rhythm that conveys its intensity all come together."
Beethoven's Fifth Symphony has one of the simplest motives, and yet it is constant developing throughout the piece. Understanding the development of the motive (melody or raga) is critical for writing Contemporary Classical Music. Schoenberg focuses on this in his book "Fundamentals of Music Composition", still one of the best books on the subject ever written.