That is not true. Conservatory professors give private lessons outside the conservatory structure all the time. My son has been taking lessons from such professors (from top-5 conservatories) ever since he was a little boy. It’s all about promise. Yes, there is an audition, but not with the conservatory, but with the professor in question. If he went through the conservatory then at best he could take lessons from a pre-conservatory prep teacher. Who are good, but not the best. The actual conservatory teachers all give private lessons but only to a small handful of kids who they choose by audition. I believe there is a kid from Florida who takes composition lessons from a certain rather well known professor from Julliard actually over skype (isn’t technology wonderful!). I know this kid as I know all the top-5 HS kids in the USA who keep winning the top-5 composition competitions in rotation and between themselves. Anyway, having been in the middle of absolutely top-echelon US music kids and their goals and destinations, I happen to know the structure very well, far better than I understand colleges.