The key is to understand the spiritual concepts of the old through faith. As we know according to Jesus' words that nothing will be taken from the law and the prophets, (nothing) until all is complete, and heaven and earth will pass away. Jesus also said that man will live by every word that God has ever spoken. Therefore, to indicate that anything in the old has vanished is very big mistake. If we have this mindset, we can understand scripture as it was originally intended to be understood.
Proving the point, the Old covenant contains promises of a new covenant. Consider the wine skins that you mentioned. The new cannot promise something that is already done. So the wine of the new covenant cannot make the old as good as the new is, for if it could there would be no reason for the new. On the same token, the old can promise something that hasn't happened yet. So the wine of the old can be consumed for the sake of understanding that the new is better. It's just like the garment Jesus talks about. The new garment doesn't need to be patched, but why take new cloth, trying to make the old garment like new? Yet we can see the the old and new garment, and the old and new wineskins are containers of wine and body. So the covenant is the container of God's word. What's inside these containers is still relevant.
Yes, the Old is relevant given to Christian Jews or Gentiles, in order to know the imperfection of the flesh/carnal man and minister them to those who are in ignorance and about the promised coming liberator who has come and has accomplished them for all of us and now being born again, we thrust froward to practice the New.
This is our witnessing and our confession of spiritual knowledge faith to the world, while we are practicing the words of spirit and life of JESUS according to the New towards one another first and be fruitful.
What is written in the Old is a proof, a reflection and are still living references of the promise of GOD to Abraham trough one of his single 'offspring', which have come to pass through HIS MESSIAH. And that through the single 'offspring' for the future are Christian, of the New Testament for CHRIST now representing the Kingdom of GOD and not anymore man as according to the Old. JESUS upon accomplishing the bitter Old, therefore gives way to GOD's already established New Covenant that rules the New generation forever, that HE has made with those who have been resurrected with CHRIST, that manages and leads this generation to eternal life.
If this New generation neglect this New Covenant management written in 'The Book', and govern HIS people future Kingdom order, then there will be confusion and division, like it has happened in the Old and history has repeated itself.
So let us all wake up from our sleep and grow spiritually by the Help of the HOLY SPIRIT and bring out the New and Old treasure of the Kingdom of GOD correctly.
In the New Testament we witness the Apostles have performed them correctly, in highlighting the New and Old treasure, from the Gospel of Matthew to the book of Revelation, for us to witness ourselves as one sound doctrine and imitate them.
Thus says the LORD;
"Ever learning but never come into the knowledge of truth."
Why are we wasting the LORD's time and keep on wrestling like children the HOLY BILE, when as Christian 'A Gathering', neglect a lot of things that has been established in the New Covenant, supposedly to already show reflecting in us 'abiding' in the words of our LORD JESUS CHRIST. The early church did not have the HOLY BIBLE, but persevered persecution to produce them for us by the will of CHRIST for GOD HIS FATHER and anointing in us the HOLY SPIRIT to be our Teacher.
The Old Testament included in the HOLY BIBLE are for those who are in the flesh/carnal ignorance but the New Testament is for believers in the SPIRIT/spirit sound doctrine knowledge Old and New understanding moving forward and not looking back what they have buried the flesh/carnal man's even in understanding in what is Spiritual.
Stephen in the book of Acts did not waste time in teaching the Jews what they have already know but proclaimed from the Old, through Abraham the promise and of the New to come and the New has come, and is JESUS, whom they have crucified.
If we go on like others in childishness and youthful passion in discussing the HOLY BIBLE, we are still in the flesh/carnal understanding proclaiming them. We only drag on and on in our discussion and go around in circles and get nowhere, to what has already been established and justified and is a written proof taught by the HOLY SPIRIT.
This information is Spiritually sufficient for us to grow up, imitating the Apostles and how they have proclaimed them, and is written in the HOLY BIBLE for our taught witnessing.
Please, i do not want to continue further, for there is a lot of work to be done in the field.
Thank you and GOD in CHRIST bless and Good-by for now.