This is strictly by your own fallible reasoning. St. Irenaeus sees the reason perfectly well:
it was possible for God Himself to have made man perfect from the first, but man could not receive this [perfection], being as yet an infant. And for this cause our Lord in these last times, when He had summed up all things into Himself, came to us, not as He might have come, but as we were capable of beholding Him. He might easily have come to us in His immortal glory, but in that case we could never have endured the greatness of the glory; and therefore it was that He, who was the perfect bread of the Father, offered Himself to us as milk, [because we were] as infants. He did this when He appeared as a man, that we, being nourished, as it were, from the breast of His flesh, and having, by such a course of milk nourishment, become accustomed to eat and drink the Word of God, may be able also to contain in ourselves the Bread of immortality, which is the Spirit of the Father.
Now it was necessary that man should in the first instance be created; and having been created, should receive growth; and having received growth, should be strengthened; and having been strengthened, should abound; and having abounded, should recover [from the disease of sin]; and having recovered, should be glorified; and being glorified, should see his Lord. For God is He who is yet to be seen, and the beholding of God is productive of immortality, but immortality renders one nigh unto God.
through [His] love and [His] power, He shall overcome the substance of created nature. For it was necessary, at first, that nature should be exhibited; then, after that, that what was mortal should be conquered and swallowed up by immortality, and the corruptible by incorruptibility, and that man should be made after the image and likeness of God, having received the knowledge of good and evil.
(IV, 38 quoted at #10)
Nobody knew what the scriptures were until 200 years later
All his reasoning is from scripture, either by direct quotations or is close paraphrase. There are two direct quotations forming the bulk of the argument, and a paraphrase in (1); a reference to many parts of the scripture in (2); seven quotes in (3), seven in (4). Contrast that with Calvin's contortions.
more Orthodoxy in his view than Catholic
Here you go again telling Catholics what their views are.
It is not my reasoning along. You, of course, understand this puts Irenaeus squarely at odds with Augustine's, A Treatise on Predestination which you reject. Shall I start quoting that. We might as well pull this or that out of every writer. It won't matter because NONE of it is inspired writings.
Irenaeus statements are interesting but it really doesn't change anything. It only validates my point that in the western church two views were held. Irenaeus comments would not square with the Council of Oranges decrees.
CANON 2. If anyone asserts that Adam's sin affected him alone and not his descendants also, or at least if he declares that it is only the death of the body which is the punishment for sin, and not also that sin, which is the death of the soul, passed through one man to the whole human race, he does injustice to God and contradicts the Apostle, who says, "Therefore as sin came into the world through one man and death through sin, and so death spread to all men because all men sinned" (Rom. 5:12).
CANON 3. If anyone says that the grace of God can be conferred as a result of human prayer, but that it is not grace itself which makes us pray to God, he contradicts the prophet Isaiah, or the Apostle who says the same thing, "I have been found by those who did not seek me; I have shown myself to those who did not ask for me" (Rom 10:20, quoting Isa. 65:1).
CANON 4. If anyone maintains that God awaits our will to be cleansed from sin, but does not confess that even our will to be cleansed comes to us through the infusion and working of the Holy Spirit, he resists the Holy Spirit himself who says through Solomon, "The will is prepared by the Lord" (Prov. 8:35, LXX), and the salutary word of the Apostle, "For God is at work in you, both to will and to work for his good pleasure" (Phil. 2:13).
- (Some of) The Canon of Orange