I think nepotism in artistic talent jobs like acting and singing is actually significantly less egregious than the nepotism that happens in normal work forces. No matter how much nepotism helps an actor get a job or a singer get a record label, if they suck they will still suck and people will know, it will affect the kind of jobs they are able to get even if their connection keeps them in the door for some work.
Meanwhile, when someone in an office or something rises to a higher up position because their dad owns the company, and they suck, this person is going to be a terrible manager ruining workers days for as long as they want, and no one will really know outside of the direct workforce they interact with. This also in general touches on the fact that nepotism in many industries helps people rise to levels of authority, but its not really the same in artistic industries as often. No singer whose parents helped them land a record deal is going to be in a significant position of authority over other up and coming singers the same way.