I think that's just due to lack of experience
I'll agree that singing lessons develop what's there rather than "creating" something new. Quite literally, what you were born with is all you have to work with - you can't "get" a higher voice or a more flexible vocal chords, however you can develop your voice to its full potential (and learn technique, there's nothing worse than nodules!).
I'm not familiar with any "commercial" vocal singers however I strongly advise you to do your homework before entering a class. Stay AWAY from group classes - singing is really only decent when one-on-one. Remember that "good singers" are not always good teachers, and try to find one that's experienced, and experienced in the field you wish to learn.