What mechanisms exist for connecting composers and performers?
Okay, I know what they are at the John Adams/SFS/LAPO or Magnus Lindberg/NYPO or Mark Adamo/SFO level: organization wants a new work from a prominent composer, the organization or the music director knows or likes a particular composer, a big-money donor wants to sponsor a new work, etc.
Then there are famous new music ensembles like ICE and Bang on a Can.
What happens elsewhere? How do composers and performers find each other?