The Conductor (Human) and The Musician (Automation) in the Orchestra.

Automation makes sense for highly repeatable and fewer variations operation-patterns overall. So, not everything is efficient by being automated. And then, there is Machine Learning will be implemented heavily in the near future... to learn the new various patterns as working and adapt if the same rare events (part placement etc.) occur in the future. However, we still need to learn Six Sigma using advanced analysis and statistical methods to improve on quality.

Basically, The Conductor (Human) and The Musician (Automation) in the Orchestra. Tesla's Gigafactory is operating 90% automated.

 

Take a tour inside Tesla’s first Gigafactory | CNBC Reports (https://www.youtube.com/watch?v=vv1mFAMz0PE)