In the 1960s, composers turned from classical music to jazz, and pop and rock, to introduce fresh energy to their film scores. In many cases, music was written specially, but then directors started selecting existing pop songs, dispensing altogether with a composer of original music.
Did You Know?
[Neil Brand has already mentioned that director Quentin Tarantino does not use composers for his films because he does not trust them with his films. He then illustrates how many pre-existing songs and pieces of film music he uses in his films
Quentin Tarantino, a master of utilizing the pop song, uses composers, all right - but only when their music is already iconic, revealing the debt even he owes to the history of the movie soundtrack.
References Reservoir Dogs