I am still reading 'Jesus through Middle Eastern Eyes' by Kenneth Bailey. In chapter 28 he reflects on what he calls the 'parable of the compassionate employer'(Matthew 20:1-16). He reminds the readers that this is another parable which has a 'missing ending'( like the parable of the Prodigal Son).
He suggests that the parable reaches a "critical dramatic moment and stops".
"What is the response of the workers who are complaining? We are not told. The readers/listeners are challenged to find themselves in the story and to bring it to an appropriate conclusion in their own lives.
A summary of the parable might be - He comes to us where we live; He loves us as we are."
"Once more Jesus creates a ‘house’ in which readers/listeners are invited to take residence as they make the worldview of the parable their own."