It could be just my experience, but homogeneous teams have higher churn rates. What happens 6 months after 9 out of 10 juniors you hired want to become team le

It could be just my experience, but homogeneous teams have higher churn rates. What happens 6 months after 9 out of 10 juniors you hired want to become team leads? Or they dissagree on the technology stack? The advantages of younger people are numerous however: you can pay them less, make them work longer hours, make silly promises they will believe (think Elon Musk fooling his employees he's going to Mars).