Comment by gampleman

Except this tends to only get really "interesting" at the top. That's because the middle layers can call on their peers or even on their superiors in times of crisis. Hence peasant rebellions basically never succeed, since their aristocrats will simply apply to the king or to their peers to help them crush it.

But the king has no superiors and even his peers are not quite as much available, so the politicking at that level gets much less stable.