Since God created Adam in Gods Image, that necessitated his future regeneration, because Gods Image lies in man being conformed to the Image of Christ, His Son, who is the Image of God. Chirst is the standard of Gods Image, not adam as a natural man. 2 Cor 4:4A further thought. When God breathed life into Adam, I believe that points to the idea that Adam was made in God's image, as we all were. That was Adam's creation, not his regeneration.
When Jesus breathed on the disciples and told them to receive the Spirit, He was prophesying the day of pentecost as well as referencing what happened to Adam. The Father's breath is our birth; the Spirit's breath is our rebirth. And while I don't think it is quite that simple, there is a truth to that statement.
In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them.
Rom 8 29
For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren.