Agreed. Whilst it's less obviously impactful, I think it's important to note that it doesn't have to be a whole person-swap though. Group dynamics can change o

Agreed. Whilst it's less obviously impactful, I think it's important to note that it doesn't have to be a whole person-swap though. Group dynamics can change over time as the people in it have different life-events, hit different points in their career-path etc. That change can then go and have exactly the same kind of effect that you outline, without any people-swaps.