Christianity is Following The Lord Jesus Christ and maintaining a relationship with Him by picking up your cross (crucifying your flesh so you can walk in His Spirit, thereby being victorious daily in your life here on earth.)
God would NEVER allow the "corruption"
Oh but He most certainly did just as illustrated many times in His Word. The very fact that God sent His only Son to earth was to straighten everything out. Who do you think He was up against other than the Devil....The Priests!
Man will always be corruptable, because of the flesh
There's a difference in putting your trust in man and putting your trust in God. Eve trusted the serpent instead of God. Adam trusted Eve instead of taking God's Word to heart. According to your tone, you are rejecting God's Word in favor of holding on to a system. Anyhow, as in your words, is 1500 years running. The Word says we are but a vapor in time and a thousand years is but a day to God
Salvation is a "change", not a gradual process of "changing" because the only possible provision for the "change" was already made at a specific point in time, long ago at Calvary's Cross! The idea of "Process Theology" actually has it roots from a Grecian philosopher named Heraclites who viewed reality in terms of "becoming" rather than "being". Heraclites claimed that "...the basis of reality was change and flux." In past times, Catholics have primarily focused on the traditional "saving works" of the sacraments, the most important being the Mass, which perfectly demonstrates the theology of "process salvation" itself. The Mass constitutes the perpetual re-sacrificing of Christ as provision for a "process", while the Cross was the provision for a completed rebirth.
The re-killing of Christ in the Mass (since the Catholic Church teaches that the bread and wine turn into the literal Body and Blood of Christ, a.k.a. "transubstantiation") is a horrific work that the Catholic would not feel necessary to repeat if he or she believed that Faith in Jesus' one-time Sacrifice had been sufficient
So again...What is the object of your faith? Is it the Cross? or is it something else
Church actually means "Called out". All the Apostles were followers of Jesus Christ because He called them.
I grew up Catholic and went through 8 years of Catechism. Some of my family still call themselves Catholics. I certainly don't attempt anything other than reaching out to them in love. I just want them to know the depth of love the Lord Jesus Christ has for them. I pray that the eyes of your heart be enlightened, so that you would know, what is the hope of His Calling for you.
Jesus states: "You must be born again"
Catholics believe neither that it is possible to kill Christ again, nor that the Mass is a "re-killing" of Christ:
268 A. ... in the Mass there is no real shedding of blood nor real death, because Christ can die no more. Baltimore Catechism
265 A. The Mass is the same sacrifice as that of the Cross. Baltimore Catechism
I grew up Catholic and went through 8 years of Catechism
It's unfortunate you didn't pay attention because if you had you wouldn't have so many misconceptions about the Catholic Church.