The physical side can play a big part if you don't have the best teeth to be a brass player. That means that there's always going to be a hurdle to be overcome before being able to reach the neutral starting point enjoyed by others with "film star" nashers.
When I first got on this forum I posed a question about that. Some dental "experts" chimed in that it didn't matter. I thought it was poppycock at the time and five years later, I still do. Straight teeth are an asset, much like good health in general.
I wonder if that applies to size and shape of chops as well.
Incidentally, I like the way you phrased your post! I think that is a very, very valuable way to conceptualize it.