While I guess they fall in the Classical genre (because Williams actually gets entered into the top 100 with the March of the Empire), I don’t know if this was the initial intent….
But if you had to add people to the list of current composers (besides the correctly mentioned three of Williams, Horner, and Goldsmith), I think Bear McCreary, Hans Zimmer, and Clint Mansell are worthy canidates to be looked at…I guess the first 3 would be one generation and then the second three would be the next generation of worthy composers.
Besides, if you want to dork it out, would you be referring to just the classical era, cause (while there was an overlap), Beethoven and Tchichovsky are in the Romantic era, and would then be ineligible.