How do you justify that Danny Elfman does NOT belong to a list of "greatest composers"? I think "greatest composer" is a qualification also open to score composers, and not only to composers who are plainly listed in antiquated schoolbooks, as you are obviously believing. What counts is musical quality, don´t you think? If not, this thread should be titled "Greatest composers as listed in the schoolbooks". Maybe your opinion will be considered ridiculous in a future when composers like Elfman, Zimmer and Jablonsky are seen as composers not less respectable than Schostakovic or Tschaikowksy.
List of 21st-century classical composers - Wikipedia