What you say is true. Whenever I form a technical team I gather around me people who fill in the gaps in my own knowledge and experience. But, it is true that one has to have a certain level of knowledge and experience to know where the gaps are. In the case of a manager, they have to have enough experience to know that they need more experience and to thus gather around themselves people with that missing experience. For this to work, it is necessary to put pride aside, for both the manager and those hired.