Thomas Mann and the children of successful parents, yet again.
The frequency with which distinguished persons have worthless children is, of course, one reason that monarchy turned out to be a poor solution to the problem of choosing rulers.
At the very least, Bayes gives us a good reason why distinguished people will almost always have less-distinguished children. Then there are all the entitlement issues — it’s easy to grow up being a jerk if you have a rich, famous and/or powerful parent. The money and power buy lots of advantages about which it is easy to be thoughtless, as does the treatment from other people.
But there’s also the issue of self-definition, which happens within a family and has only a tangential connection to the power a parent may wield in the outside world. Any kid of a distinguished parent is going to waste time and energy thinking about how to distinguish themselves in opposition, in competition, in some kind of relationship to the distinction their parent has achieved. Waste, because that time could almost always be more profitably be spent actually learning and doing stuff, and figuring out what one wants to do without reference to the family business.
(insofar as some royal and other dynasties have done not entirely disastrously, I’d say it’s because they’ve established formal or informal training programs that take much of the emphasis off following the immediate parent and put it on the profession itself.)