Apple is not a company where general managers oversee managers; rather, it is a company where experts lead experts. The assumption is that it’s easier to train an expert to manage well than to train a manager to be an expert.

In a 1984 interview [Jobs] said, “We went through that stage in Apple where we went out and thought, Oh, we’re gonna be a big company, let’s hire professional management. We went out and hired a bunch of professional management. It didn’t work at all….They knew how to manage, but they didn’t know how to do anything. If you’re a great person, why do you want to work for somebody you can’t learn anything from? And you know what’s interesting? You know who the best managers are? They are the great individual contributors who never, ever want to be a manager but decide they have to be…because no one else is going to…do as good a job.”

https://hbr.org/2020/11/how-apple-is-organized-for-innovation