Playing by ear, or working with a small band is one thing. Putting together music for movies and TV, where you are working with many highly trained people who get paid by the hour, in studios that are rented by the hour, I would think economics alone would dictate sheet music, scores, etc., the infrastructure and literature of musical performance.

In the olden days, even non-musicians, like dancers, choreographers, and vocalists had to work with orchestras on arragements, many of which were constantly evolving and being rewritten during rehearsals. A knowledge of musical notation was very important. It's not garage band stuff. You can be illiterate and a poet, Homer was, but its a lot easier if you can write it down.

Music is like mathematics, its a man-made universe independent of the physical world. Oh sure, its all about vibrations in air, but its more than that, just like math is more than just symbols on paper. Mathematics can be used as a tool to explore physical reality, but it is NOT the same thing. Likewise, music can explore emotional reality, and it can communicate in that world. Music, math, and language are remarkable things that humans do to create the universe they live in, a universe very different from the particle and wave, force and field universe that physicists usually think of when they mean "reality".

Watching a good band at work, the way they anticipate each other's moves, communicate almost telepathically with one another, and put together a performance that moves an audience of non-musicians to an emotional and intellectual experience is a marvelous thing. There is communication of a very high order going on, and for those who cannot see it, it is impossible to describe or explain it to them. When the band is really hot, and when they are really cooking, and when the audience is hooked into that linkage and contributes emotionally to it, it is an astonishing thing to watch, if you're a part of it, it brings tears to your eyes because you realize you are seeing the truth.

I wish as a young man I had dedicated my life to music instead of to science. I have no guarantee I would have been any more talented at music than I was(n't) at math, but I would have loved to find out. Like science and math, I think its worth failing at to find out.