Citation needed.
Fact: Many existing transit services originated as private companies.
Funding often came from business, retailer, and real-estate interests: increasing the availability of transportation increased the availability of employees, of shoppers, and the value of housing.
On a large scale, though transit companies are hugely capital intensive, require close coordination with other entities, and tend to have positive externalities which limit the ability to fund operations strictly out of farebox revenues.
A large number of non-BART commuters, employers, retailers, and others, are about to discover the value of the transit system, which moves over 370,000 riders daily.