As I pondered this parable, I had a different question come to mind: "Was there anyone who worked the whole day and was pleased and content with their pay? Was there anyone who worked the whole day and realized that they had peace the whole day because they had work? Was there anyone there who did not complain?"
The parable was not a news event. The story was not intended to answer all our questions. Jesus understood people. He knew most people in that situation, people who work the whole day, would grumble to the boss about getting the same pay as those who worked one hour. Jesus knew the human nature of people. We would all complain, wouldn't we?
That made me think of the the parable of the prodigal son in Luke 15:11-32. The Father in this story had two sons. One didn't want to stay with dad. He wanted to go and do his own thing. He asked dad for his inheritance, and off he went and lived wildly. The older son stayed home with dad and fulfilled his obligations. However, we discover that his heart was not at home. So, this begged the question: "where is the son who loved dad, wanted to stay home with dad and help him in any way possible? He didn't exist in this parable. Does he exist? Jesus accurately portrayed human nature once again. Sons are either rebellious, or they are obedient with resentfulness. Jesus didn't have a good son in this parable. What he had was realism. Jesus knew human nature.