The fact is, Max, that the question was phrased very poorly and the Beethoven answer would be appropriate only if one was referring to the History of Music, (although good arguments could be made for Tchaikovsky, Brahms, Hayden or many other classical composers, as well).
The Sinatra answer would be appropriate to the history of Popular music (along with any number of big bands from Harry James to the Dorseys or Benny Goodman or Composers of Musicals like Irving Berlin, or the Hammersteins, or many many others), and moving into and through the Rock era one has to consider Elvis, Chuck Berry, Bob Dylan The Beatles, The Stones, and any of those who had a major influence on the music of our heritage.
I suspect, However, since the MUSIC INDUSTRY was cited, and based on Jacob's own suggestion of who he considered appropriate, I assume he is looking for someone who's popular or hot at the moment, which is a pretty SHALLOW question to consider, unless he wants people to defend their selection on the basis of their ability to actually have a major INFLUENCE on the Music of today and Tomorrow, and that's a totally different topic.
At the very least, I think Jacob has to define his terms if he wants any meaningful answers.
Jim Hoye, (JRH)