One of the reasons put forward for Wales and England combining with relatively little trouble is that it allowed the Welsh nobility to change from a similar system to that ogf primogeniture, where all the land goes to the firstborn son. The problem with equal splits over time in the eyes of the powerful is that it gradually weekens the power of the nobility as they come to have less and less land concentrated.

Any idiot can face a crisis - it's day to day living that wears you out.