Well that is the question, isn't it. What qualities are passed on to their children? It is actually fairly common to see ideological continuity between parent and child (eg, most members of a religion had parents from that religion). So there is a case to be made that if you have a subgroup of society with unusually clear governing principles it makes sense to put them in change and have their children continue to be in charge because it has a chance of preserving the principles. In the optomistic case they can propagate for generations. That does actually appear to be what happens historically in successful countries where a hereditary or semi-hereditary ruling elite form with strong capabilities and shepherd everyone to success for a few generations before their abilities mean revert.

That being said it is comparatively a terrible way of doing things vs a more mathematically and psychologically sound system. Electing people really is the way to go, all these "stable" political systems are stable at being worse than just letting people vote for everything. As the saying goes, dead is stable. Stable isn't great if unstable means the capacity to rapidly improve.