The behavior of the landowner is certainly strange- paying everyone the same no matter how long they worked in the vineyard. And if we were the first ones in, we would probably feel like we had been badly treated. But there are a few things to consider. First, it really is the money of the landowner and he can do whatever he wants with it. The first workers agreed to and received exactly what they had hoped for originally. Any normal day they would have gone home satisfied that they received a fair day's wage for a fair day's work. Second, in those days a daily wage for a worker was generally tied to what it actually cost to live for a day. Whether you work or not, you have to pay your rent and feed your family. The children are not going to be less hungry because dad only worked half a day. It certainly does not pay to have a pool of available workers that are desperate and hungry men. You may have to depend on them tomorrow. If they are malnourished or ill from being homeless or preoccupied because their families are in want, what good is that for anyone? It is best for the common good to provide for all the workers. And the common good benefits everyone- landowner and worker alike.
But the Gospel is really not about vineyards, although we could learn something from the behavior of the owner. The story is really about the kingdom of God. The vineyard is the kingdom and the landowner is the Lord, and we (hopefully) are the workers.
Note that the workers may be waiting around, but they depend on the landowner to hire them. It is he who seeks them. We may think that we do this or that for God and that we are wonderful workers for the Lord (and that may very well be true). But we are all dependent on the Lord. It was not you who chose me, but I who chose you said Jesus to His disciples. Sometimes we forget how utterly dependent we are. God has given us existence, which no one can obtain for themselves. For many of us, God has given us the gift of faith and even the opportunity to receive it. And if we do serve the Lord, it is at His bidding. We cannot build His kingdom apart from Him.
Furthermore, we have no control over who God chooses. It is true that the Church has been given authority to decide the suitability of ministers. But that authority is God's that is given to us. It is not apart from Him. If we choose inappropriate or unsuitable ministers who do not actually have a vocation, then the whole Church suffers. In truth, we are all called in some fashion or another to serve the kingdom of God, but our happiness and true success will result from our obedience to the Lord's call and not to our own desires or to the fashions of the times.
The reward for service is not a result of the length of service, but rather fidelity to the will of God. As workers in His kingdom, we should rejoice that others have also been called and are receiving the gifts of eternal life. If we do what we are asked to do with joy, then we will receive all we hope for and even more. There is no reason to be jealous of the gifts another has obtained, especially when all of us are dependent on the Lord.
There is one aspect which is missing from this parable, maybe it is what Jesus is getting to when He chastised His hearers for failing to convert when the tax collectors and prostitutes changed their lives and repented. Even though we are workers in the vineyard, that is not our actual position. And as long as we think of ourselves as merely servants we will miss the true blessings that the Lord wishes to bestow upon us. In truth we are not merely servants, we are even more than friends, we are children. The vineyard is not merely our workplace, but our home. Our "pay" is not the amount that is necessary to survive another day in a cruel world. Rather, our remuneration is an eternal inheritance: eternal life in joy in the home of the Father.
If we understand that we are children and not slaves we can understand the generosity of the Lord. If we are His children, it is His desire to have us share in everything. And where the love of a family really exists, it is not divided by the numbers of the members, but it is multiplied by them.