This is a very unsatisfactory answer - but you have to grow a culture. Working with people to match their personal goals with organizational goals. High degree

This is a very unsatisfactory answer - but you have to grow a culture. Working with people to match their personal goals with organizational goals. High degree of mutual trust. Cooperative design. Group ownership of the codebase and rotating responsibilities. Lack of 'magic knowledge'. Sufficient infrastructure development to reduce rote workload on developers. All of these are organic rather than formulaic. They require limited rates of growth to enculturate the new hires, and a seed group that understands this. That works. But you can't hire a consultant to build that, or write a book about it. And bad elements in the mix can mess up the whole thing.