@Allison said, “My understanding is that most of the major orchestras have a sign-up sheet every year for those interested in solo opportunities, and most members sign up. (I have no idea what the Minnesota Orchestra does in this regard.”
When I was studying with the MO Principal Flute it seemed that he was ‘tasked’ with performing as a soloist from time to time. I don’t know who chose the pieces. This was something he did not seem to relish. And there was an occasion when, to my distress, he vehemently objected to having to perform a duet with Rampal. Hopefully, it is better now.