After Adam and Eve sinned, why did God not destroy the world and start over to achieve a better result?
The short answer is that a fresh start was unnecessary.
God knew he would still accomplish his ultimate goal, even though Adam and Eve disrupted his initial plan.
God’s plan at creation was to commune with us forever as we lived a thoroughly fulfilling life—in perfect health, in an ideal world he designed for our enjoyment, in perfect harmony with everyone and everything in it.
God is sovereign and omnipotent. Nothing can preclude his eventual success, including the messes we make.
So instead of abandoning his ultimate goal after Adam and Eve sinned, God simply devised a new strategy to achieve it.
He implemented a reclamation plan for us and the world.
God restored our ability to commune with him eternally by paying the penalty for all sin through the death of Jesus.
He will eventually give us perfect bodies that live forever. He will also upgrade the universe and bring heaven to earth.
There we will live in perfect harmony with God and each other. And under the leadership of Jesus, we will build a harmonious society in which everyone thrives, individually and collectively.
Reborn believers will enjoy in the next life the utter bliss God originally intended for everyone to enjoy in this life.