Why does a choir, backed by a big company like Boeing, need to charge anything?

The choir used to be able to give free concerts, but company support has declined to reflect current economic realities. At this point, the company still generously provides space for rehearsal and storage for our music library and piano but unfortunately does not give us any financial support. So in order to cover our expenses, which include the services of our director and accompanist, the purchase of new music as well as the usual business expenses of insurance, licenses, royalties, etc. we must seek contributions from our audiences. (By the way, we could never afford to pay our director and accompanist what they are really worth to us.)