I wonder at directors: It's hard enough to find artists with the insight, vision, expressiveness, and mastery of their craft to create great art.
But before film, artists worked mostly alone. I suppose architects and composers have had to be mindful of the performance of a bunch of humans, but didn't necessarily have to manage that process. Stage directors obviously have similar jobs, but necessarily at a much smaller scale, with fewer technical demands, and by my limited understanding, stage directors lean toward overseeing and facilitating the art, which is more a product of the playwright and actors.
But film directors - as artists they must be all those things an artist is; and also they must master more domains than most artists - film, audio, script, story, costumes, sets, lighting, etc.; and on top of that they must be top-notch managers: hire and manage hundreds or thousands of highly talented people (just look at the credits), and then coordinate them all to finish on time and also manage a budget in the 10s or 100s of millions, and then also sell their vision to funders.
Where are these 'directors' found? Can they really do all that or is it handled otherwise? How are they developed? It's hard to imagine there would be more than a couple of them.