The financing can be complex, but broadly there are a few things that enable modern American orchestras to survive.

1. Benefactors who give money to the orchestra, rent boxes, etc. 2. Popular (non classical) concerts which have a possibly larger crowd and varied material. Harry Potter with orchestral accompaniment? Tenacious D with orchestral accompaniment? The musicians hate it, it pays the bills. 3. A mostly part time staff. Most orchestral musicians will play in many orchestras, teach, etc.

They made a loss on your concert. But they knew they would.