Much like the terrible person who regularly attends church, there are plenty of people who leave school rather stupid. Affiliation with an institution may be an indication of a possible something, but is a guarantee of nothing.
One of the rarely spoken truths about academia is that a degree is decidedly not the same thing as an education. It often seems that the obsession and pressure to get a degree and to have a credential has surpassed in importance the benefit of actual knowledge. Well, congratulations. That sort of thinking can get you a $120,000 piece of paper.*
Now, it would indeed be hard to go through your schooling without learning at least something. And so people have continued to come out the other end feeling smarter, as well they should. But as school resumes this year, I would encourage any returning student to shake things up a little bit. Try reminding yourself that you are not there for grades. You do not exist to appease your professors. You are there you gather knowledge and improve understanding.
As a strong-willed youngster, for many years people told me I should just trust my teachers. Looking back now, I of course see the wisdom of that, but only to a point. I know I couldn’t have been the easiest pupil, and I am sure that is still the case. But as a teacher now myself, I can see some of what I had wrong and what right. And an eager student is always welcome. But the main thing I see now is that what was really needed from me was not blind trust but patience. You should not trust your teacher simply because they have that title, or because they have gray hair, unless of course your questions are about the maintenance of gray hair. But in that case how much "trust" is required? It is demonstrably the case that they have first-hand knowledge of graying hair! One should trust a teacher because the things they say consistently make sense. Not out of awe for a position they hold, or because the things they say are dazzling. One should always be wary of dazzle. They should make sense, meaning that one thing should follow another in a way that makes sense.
Singing, as a course of study, is sometimes subject to a respect/fear dynamic. Not every teacher is a tyrant, of course. I don’t mean that. But what I mean to say is that there is often such a degree of reverence paid to teachers that they are not questioned or pressed to explain. Students often defer to their teacher to a degree that they end up failing to even get what they pay for. Moreover, a teacher who has been a respected performer may indeed be a great instructor, or they may not. But you are not under their tutelage for their reputation as a performer. If you are, that is foolish. You are there to learn. You are there for your reputation as a performer, and hopefully for their prowess as an instructor. Being a poor singer, but student of some grand person is useless. Being a fine singer who learned from a knowledgable person.... Well, that might actually get you a job.
Some people will tell you that it is sufficient to trust a teacher because what they say works. Even this I find to be insufficient. On the one hand, I agree with the dictum “Use what works”, but here we are not only discussing application, we are addressing education. Don't just trust a teacher because what they say works. Trust them because it works and it makes sense. If I were to tell you to pretend that your nose is the propeller of an airplane, and suddenly singing was made easier for you, that's wonderful. But unless you understand why that image works and is helping, you can't be truly said to know anything more about the skill of singing.
Now I would like to highlight again that what I'm discussing here is specific to Education. Not to activities. If you want to go out and feel your way through something, wading through sensations until you're happy with a resulting product, by all means do that. But I wouldn't advise paying thousands upon thousands of dollars for somebody to be your cheerleader. The purpose of an education is for you to dive into genuine inquiry with the advice and guidance of someone who has learned some things in advance of you but hopefully continues their own journey.
*In its most recent survey of college pricing, the College Board reports that a "moderate" college budget for an in-state public college for the 2012–2013 academic year averaged $22,261. A moderate budget at a private college averaged $43,289. -https://www.collegedata.com/cs/content/content_payarticle_tmpl.jhtml?articleId=10064