Leading people in a field is different than working in that field
Business schools teach a lot of leadership. Other vocational schools do too. I don't know them as well, but I bet the following pattern applies to them. Say someone gets their MBA and gets a job in finance. They don't start at the top of a hierarchy. If they do well they get promoted to manage people like they were. Then they get promoted to manage yet more people. They keep getting promoted, always managing people in their functional area of finance. Eventually they start general management, where they manage people who do things different than anything they have experience…