The kingdom of heaven is always a contradiction of common kingdoms that operate according to survival of the fittest where the winner is the one who dies with the most toys. So the all-day workers sweating in the sun obviously deserve more wages than the slackers who spent all but the last hour of the day playing 42 (the official domino game of the great state of Texas) in the marketplace. You can bet that the next time the master went looking for workers the marketplace had become a right to wait state and expecting a day’s wage for working one hour was the new normal. That is why the kingdom of heaven is like something that is never done in common kingdoms. Apparently God doesn't get how incentives work. But then the parable is not about the workers or even the wages. It’s about the landowner which means it’s about God and in this parable God gets to do whatever God wants to do which in this case is do something we would not. Surprise.