I think that the cat and mouse have shown both sides. I believe that there are many paths to Rome. I have stopped using the word "buzz" to stay out of discussions just like this - surely splitting hairs, but simply describing "ignition" to get the standing wave in the horn going. Without it, we are just blowing air through a tube. It is not possible to play a tone without the lips being ignited. They open and close like a switch in harmony with a multiple of the resonant frequency of the horn. The more supple the lip and embouchure, the easier that it is to play.
Now, we all know that embouchure changes (jaw position belongs to that) are a dangerous thing for most as there is no applicable reference for success. In my small world, embouchure changes are more luck than skill. That is why I prefer evolution to revolution. I do not ask (or care) the player if they phoo, BRRR or ZZZZ. They play long tones with NO ARTICULATION. The lips must ignite on a whisp of air. I try and stabilize the geometry regardless how it lies. Then the player gets a steady diet of long tones and lip slurs to build and strengthen. Once the art of creating sound is stable, we add microscopic amounts of articulation to chop the tone into intelligible pieces. This is like learning to talk and in my international experience is VERY tied to the players mother tongue.
Now, moving the jaw could very much change the playing field from downstream to upstream with dramatic changes to the geometry of playing. I know many upstream players with great high chops, but also know enough downstream players that also are not slouches (do we change embouchures for any other reason?). I have not investigated this deeply. Those students that come to me for lessons get the evolution routine regardless of what they bring to the table. Some fly with it, others just get more stable.
Now, one word of warning. I learned first hand at TrumpetMaster that pedantic, repetitive posting never results in anyone taking ones side. Generally the target audience just goes away shaking their heads. Sometimes passion is too close to politics or religion (with a small R).