Upon reading this screenplay, I realize that Fletcher and Neiman are both, at their core, the same character. There are cut scenes present in this script that exemplifies that relationship much more than the movie does. We see a more well rounded Fletcher, one who truly loves the students that he terrorizes; studio band is the only family he has. This makes his abuse that much worse, but it also shows you that he treats those closest to him the same way that Neiman does. He pulls them in with honey (e,g the scene where he sits Neiman down in his office) and that pushes them away with his lust for success.
Chazelle has a skill for expressing theme through characterization. Out of his filmography, I think this is the one that does it best. There is so much internal conflict integral to both Fletcher and Neiman that one can place them in any setting and the dialogue will write itself. I love how these two characters simultaneously give each other what they’re looking for whilst destroying each other completely.
They both see the other as an enemy; they both believe the other is trying to destroy something that they have. Fletcher, sees Neiman's mistakes as a direct attack on the band. Neiman, on the other hand, views Fletcher as someone who exists to terrorize him specifically. While there is a lot of intentional trauma inflicted on Neiman by Fletcher, ultimately, Fletcher isn't after Neiman personally. Neiman is just the next victim he's found in his quest to find the next Parker.
Neither are able to recognize that their true conflict is an internal one and they are directly responsible for their failures. Fletcher's dream is to find the next Charlie Parker but he destroys any student of his who comes close to having the chance. His dream is also flawed from the start, as he's trying to turn a student INTO Charlie Parker. He won't find the next best of the new generation by squishing any and all potential into a Bird shaped box. Neiman's dream is to be the best, not happy, and these ideals create the breeding ground for Fletcher's abuse. Only someone so focused on being the best would let someone crush them down to nothing in the name of this goal. These shortcomings are entirely internal and we see how they manifest in both character's behavior. When Neiman finally grows a spine by the last few pages, we, the reader, are overjoyed to see him become himself. However, Fletcher is also happy. He got exactly what he wanted, and in doing so, lost both Shaffer conservatory and the band in this obsession while his personal life become fractured (there are hints of both a wife and child that he's lost due to his erratic behavior). Neiman also got exactly what he wanted, and in doing so, lost both Shaffer conservatory and the band in this obsession while his personal life become fractured.