Bay Area Management Profiles

In the Bay Area Tech companies what is the typical (is there such a thing?) management profile look like? Were those individuals some of the best ICs that had both the ability and desire to manage and lead people? Were they more just solid technically with the ability and desire to lead and manage? Do they tend to remain highly technical and involved in in depth tech discussions and drive design or do they more tend to work to provide guide rails and let the teams do what they do best? Are most of the management folks internal hires or external or does it vary by company or level of management?