Here are some thoughts for anyone reading this…
The biggest affect of changes in leadership is not a new leader’s ideas and strategies. It’s the change in the motivations of former subordinates.
When a leader is replaced, the immediate effect is constraints that were placed on subordinates are removed. Sometimes these constraints are explicit directives and sometimes they are due to implicit motivations.
Employees don’t challenge their leadership, they just stop working for them.
Employees who don’t respect their leadership often use indirect means of undermining their work. A good read on this topic is Simple Sabotage (affiliate link) . A change in leadership has the intimidate effect of giving the workers the motivation to show that they are not the problem, and their former leadership was the problem.
Teams are successful only when they are willing to cooperate as a group to succeed. There are no single successes.
Good leaders can be effective, set strategy, and direct the course of business. Just like every other worker, it takes time for them to do this. Therefore, any alteration seen in the overall effectiveness of a team due to leadership changes are due to the willingness of workers to succeed where they were not before.