The fruit on the tree did not cause Adam to fall. It was identification with the kingdom that gave him the forbidden provision. Adam's nature is branded as identifying with evil. That is why justice demands that Adam go where Satan goes.
"Then he will say to those on his left, 'Depart from me, you cursed, into the eternal fire prepared for the devil and his angels.' " Matthew 25:41 ESV
Christ on a cross and raised from the dead alone will not save a person. Identification with Christ by eating of the fruit of this new tree is what allows a person to be taken out from under the power of evil and into the Kingdom of God's dear Son and given a new nature.
"He has delivered us from the power of darkness and conveyed us into the kingdom of the Son of His love" Colossians 1:13 NKJV
We have tried to undo what was done in the garden... but identification with evil could not be undone. Adam is sold under sin because of it. It is not the sins. The sins will bring a payment of death but the actions are not the root issue. It is the nature that is branded as identifying with evil. Adam must go to Hell. He can not be saved or rehabilitated.
The new creature must go with Christ. The new man can not be corrupted and Christ has become an anchor for the believer inside the veil of Heaven.
What Christ did has unlimited power to save anyone and everyone but not everyone will identify with the person and so they will never identify with the power that could save them.
Today each person is given an unprecedented opportunity through the possibility of identification. Identification for salvation but also identification in grace to live a victorious life.