Shortly before the advent of García, various attempts were made to establish a science of voice production based on the knowledge of physiology. This movement was given impetus by the use of the laryngoscope, and García's first belief was that his discovery would be a incalculable value and benefit in the synthesis of vocal development. Experience proved the contrary, and García's own opinion regarding its value to the vocal world was materially changed before the end of his career.
Physiology, in its present accepted relation to vocal art, must be consigned to its proper position in the minds of men, and the true living principle be reinstated. The sciences of acoustics, physiology, and other kindred sciences have the analytical corroborative value, but the breath of vocal life—past, present, and future—was, is, and shall be the science of psychology.
Warren W. Shaw, The Lost Vocal Art and Its Restoration (J. B Lippincott, Philadelphia & London), 1914: 132.
Digging into human nature. That is what I hear Shaw alluding too, rather than the actions of muscles and ligaments. While voice science has keep a steady space delving into the minutia of anatomy, physiology and acoustics since 1914, it has has only lately taken a deeper look into matters like motor learning theory which—surprise, surprise—observes that learning to sing has little to do with remembering facts and formants. It seems that singing teachers, while holding in their heads all that they are taught about the aforementioned subjects, have to figure out how to climb into the heads of their students and present experiences that enable them to sing—learning to singing being a procedural rather than a declarative process.
Speaking of procedural learning: children who learn their native language (or even a second and third language) aren't taught the anatomy, physiology and acoustics of their mouths in order to speak properly. Instead, they are given the sounds of words. Complete bodies of meaning, children inculcate these words and sounds in the most simple way possible: through repetition, feeling—which really is listening—and association, the ear organizing the movements of the body. For all that I can tell, the most successful voice teachers do something similar, which is what every parent does for a child of three; that is, they chop up everything into bitable bits of doing, which avoids choking on facts.