Symphony orchestras operate on many models. Corporate is increasingly common. Some are collectives; others resemble sports teams. There are monkish ones on spiritual missions and academic ones with a musicological bent.
Maybe it's a California thing, but our big orchestras like to think of themselves as families and credit their uncommon successes to building long-term relationships. Carl St.Clair is in his 26th season as music director of the Pacific Symphony in Costa Mesa. Michael Tilson Thomas' 20 years with the San Francisco Symphony was preceded by 20 years of annual guest conducting.