Yes
- Perform a 10-15 minute set. Be judged.
- One of the judges goes up and works - on stage and in front of the audience (which includes other choirs and bands, and their teachers) with the group that just performed.
- Go backstage to a private room where another experienced musician proceeds to give a slightly longer private training session.
The purpose of this system is, under the guise of letting schools compete with each other, teach music teachers to be far better teachers.
I don't know how much this system is responsible for the musicians that you like. Most work in categories of music that the competitions are not held in. (The ones that I remember are concert choir, jazz choir with various sizes of choir, concert band, and jazz band.) But Diana Krall is an obvious product of it.
Cheers,
Ben