We had a family doctor, too. He even made house calls.
Young people don't generally need a colonoscopy or hip replacement. Annual physicals, immunizations, treating occasional illnesses -- was nice to have all the medical records in one place, with continuity of care.
Both my kids have had the same pediatrician since they were born. He's joined a network now and is close to retirement, but we try to make appointments during his office hours. He'll see patients until they turn 21.
Required insurance networks.