Why is it so hard to communicate?

The problem with singing is that you can’t see what’s happening. You can only describe your experience. I can tell a student to curve the fingers more to play the instrument. I can’t tell a student to increase tension in the thyroarytenoid .2%, increase tension in the crycothyroid 1%, and increase airflow by 4% and still expect accurate results.
How many teachers with college degrees still tell their students to breathe from the diaphragm? What other way is there? If you want me to breathe “low”, why don’t you tell me to breathe from my toes?

So, if these college graduates can’t teach properly, how does an amateur learn ANYTHING? Simultaneously, one term in one way of teaching can be different either radically or minutely!
So, the real question is, “How can we communicate as singers if we aren’t all speaking the “same” language?” It’s crazy!