Mary is a TYPE of Eve, with Eve as the model. Eve has not been replaced. Jesus is a TYPE of Adam, with Adam as the model. Neither Eve nor Adam have been replaced, but their typology has been fulfilled. The Catholic and Orthodox accept TYPOLOGY in their theology. Many Protestants don't understand that at all. Your question is answerable if you learn more about typology. Eve isn't discarded. Mary does not negate the possibility of Eve being redeemed at all. They are two separate people. One like the other.
Adam and Eve sinned, and due to that state, they were cast out from the garden. They were fallen and helpless in that they could not work toward their own salvation. The justice of God requires punishment for sin.
God took pity on them because unlike the Angels, they did not have perfect knowledge when they sinned and were deceived. God needed to buy them aka redeem them. Redemption comes from God, not within ourselves. That is is Gospel, the good news.
God has taken upon Himself to do what we could not do, redeem us from sin.
God chose to become a man, and suffer and die for us. Sin separated Adam and Eve from God, and they had to be bought, they could not buy their way back themselves, as they would find as did Esau, that there is no space for repentance though they seek it diligently with tears.
Sin made them slaves to sin and of the seed of Satan. Mary was formed by God by His choice not ours. She is as the way He chose to enter the world to redeem us.
Consider this sermon from the second century Bishop, Sophronius of Jerusalem.
From a sermon by Saint Sophronius, bishop
Through Mary, the Father's blessing has shone forth on mankind
Hail, full of grace, the Lord is with you. What joy could surpass this, O Virgin Mother? What grace can excel that which God has granted to you alone? What could be imagined more dazzling or more delightful? Before the miracle we witness in you, all else pales; all else is inferior when compared with the grace you have been given. All else, even what is most desirable, must take second place and enjoy a lesser importance.
The Lord is with you. Who would dare challenge you? You are God’s mother; who would not immediately defer to you and be glad to accord you a greater primacy and honour? For this reason, when I look upon the privilege you have above all creatures, I extol you with the highest praise: Hail, full of grace, the Lord is with you. On your account joy has not only graced men, but is also granted to the powers of heaven.
Truly, you are blessed among women. For you have changed Eve’s curse into a blessing; and Adam, who hitherto lay under a curse, has been blessed because of you.
Truly, you are blessed among women. Through you the Father’s blessing has shone forth on mankind, setting them free of their ancient curse.
Truly, you are blessed among women, because through you your forebears have found salvation. For you were to give birth to the Saviour who was to win them salvation.
Truly, you are blessed among women, for without seed you have borne, as your fruit, him who bestows blessings on the whole world and redeems it from that curse that made it sprout thorns.
Truly, you are blessed among women, because, though a woman by nature, you will become, in reality, God’s mother. If he whom you are to bear is truly God made flesh, then rightly do we call you God’s mother. For you have truly given birth to God.
Enclosed within your womb is God himself. He makes his abode in you and comes forth from you like a bridegroom, winning joy for all and bestowing God’s light on all.
You, O Virgin, are like a clear and shining sky, in which God has set his tent. From you he comes forth like a bridegroom leaving his chamber. Like a giant running his course, he will run the course of his life which will bring salvation for all who will ever live, and extending from the highest heavens to the end of them, it will fill all things with divine warmth and with life-giving brightness.
Genesis 3:15 tells us that Mary is not of the seed of Satan, rather his enemy. He hates her because he was the light bearer, Lucifer. Now material creature will bear greater light than he ever could or will. He cannot subject her to himself so he seeks to crush her in the way that Captain Ahab sought Moby Dick. When he is cast into the abyss I can imagine him saying for hate’s sake I spit my last breath at thee. She will be sad, not for what he says about her, vile though it is, but God loves His whole creation and He is grieved when His love is rejected, as is Mary when she grieved for her Son at the foot of the cross. Jesus tells us, behold thy mother.
The hate of Satan is where we get the term, son of a b—-h, as it blasphemes Mary and Jesus at the same time. Hate of Mary, indifference or disrespect does not come from God, rather her enemy and ours, Satan. God commands us to honor our mother and father. Would God Himself not obey His own command and honor His mother above all creatures, or do we think we are above God because we obey a command that He does not ?
