Guanxi vs. Nepotism

We all wish to see our friends succeed. This is only natural. Similarly, we like to work with people we trust, primarily our friends. This naturally leads to a system of self-promotion and inclusion that is covered by the concept of Guanxi. Fundamentally, this is a good idea because it streamlines social efficiency. Like is drawn to like and by working together several people can accomplish far more than the same number of people working independently.

But where is the tipping point? When does it stop being about optimization and delve into nepotism? In the current administration we have seen record levels of nepotism, yet the actions were not fundamentally different than previous Presidents. Where is that line?