That's not how organizations work. You can't just slowly take out the "bad" people and replace them with "good" people and expect that to fix anything. It's the wrong mental model.

Organizations are sticky. They get stuck in a rut, basically. The slow trickle of new people gets indoctrinated into the Company Way (or else selectively ejected), and the people that are able to leave often use it as a lesson of what not to do.

In short, turnover isn't a magic bullet.