I would have titled the post differently, shortened it, brought out more implications, and made it less dependent on the mathematics. Still, this contribution from Heteconomist has that special something, namely insight.
The first key point is that if you learn more on the job on a regular basis (i.e., your job is interesting), you become harder to replace from the point of view of your boss. Over time you win more of the bargaining surplus. That means we end up with jobs with an inefficiently low level of learning and jobs are too boring relative to an optimum.
The post closes with this:
A different application of the argument presented here would be to consider the circumstances under which instances of bad luck in competition for employment could have long-lasting effects on the earnings of individual workers. Workers who luckily gain appointment into good jobs, perhaps initially contrary to merit, will get the opportunity to learn on the job and lock in their advantage, whereas unlucky workers consigned to bad jobs, again perhaps contrary to merit, might have a tough time reversing their fortunes.
I like the present application, though, in which capitalist deskilling emerges partly as a response to the effects on worker discipline that are potentially created by on-the-job learning.
Applications to nepotism are left as an exercise to the reader. For the pointer I thank @Interfluidity.