Appropriate training is only possible when the teacher of singing knows a great deal about a great number of things. Then, that knowledge must be applied over time because the only way to learn anything really well and own the entire experience is to go slowly. You do not develop mastery over anything in the proverbial blink of an eye.
In a society that loves fast everything the idea that you have to commit to years of study isn’t something most people want to contemplate let alone do. With singing, things are complicated by the reality that many people who have been or are now successful CCM singers have never had any formal training in singing, and sometimes in music either. Of course, the place where that is not possible, no matter how much native talent someone has, is in classical music. The constraints of the styles are such that training is a requisite, and the control over the sound itself requires both finesse and refinement. That is a big and significant difference.
The idea that Contemporary Commercial Music singers shouldn’t study singing at all in order to be “real” is a sign of ignorance on the part of artists and producers. Appropriate training should make it possible to sound authentic and personal and, at the same time, stay healthy. Not to train to be a technically secure singer is a sign that the vocalist does not understand what training is or should be.
The attitude that CCM singers should not study at all is, sadly, fostered by the idea that all singers should learn to sing classically because that is the “best” way to train the voice. They resist, and rightly so, the idea of being told they have to sound different in order to sound the way they want. Thinking that classical training is the only alternative keeps singers of many CCM styles away from any kind of singing training. That makes the possibility of vocal injury more likely. Either way, it is the singers who lose. Inappropriate training is seen as being worse than no training at all. That can be true, unfortunately.
Someday we may regard singing training as the physical thing it is and understand that training the voice to be stronger, more flexible, and more capable of singing whatever kind of music a person wants to sing is not only possible but necessary. We aren’t there now but the more people who understand the reality of the situation the faster things will get better. Appropriate training takes in the age, the kind of voice (high, low or middle), the power of the voice (lyric, dramatic), the background and history of the singer (previous experience or family history), vocal health, natural ability and the kind of music the singer wants to do. It takes in many kinds of vocal exercises, breathing exercises and ways to coordinate them in a living human being who will learn them gradually, with practice, over time. Nothing else works.