The world carries on the same way it had been.
still wars
still death
still sin
still cursed.
But you remember that Revelation 22:14-15 describes the state of the world
after the New Jerusalem has come down from God out of heaven,
subsequent to Christ's return. That New Heaven and New Earth with the New Jerusalem present still has ongoing wickedness occurring in the world, and its results. But those things are OUTSIDE the city of the New Jerusalem and its open gates. God looks at everything
within the New Jerusalem as covered by Christ's imputed perfection. Isaiah described that New Jerusalem city as having walls called "Salvation", and its gates called "Praise" (Isaiah 60:18).
"Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city. For
without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie."
What is different about the conditions in this world from
before that New Jerusalem came down and
AFTER it is revealed is the destruction of the Satanic realm. Any wickedness taking place in this world since that New Jerusalem was fully revealed is credited ONLY to sinful mankind - not to the Satanic realm, whose members were all destroyed by then.
Romans 16:20 predicted this destruction of the Satanic realm, which would be crushed under the feet of the saints
"shortly" in those days when Romans was written (around AD 60). It was the fulfillment of the ancient promise given to Satan after the Fall in Genesis 3:15. That total destruction took place after Satan's "
short time" in the first century, since John said that this particular "
short time" after Satan's release had already begun, even
before he started writing Revelation (Revelation 12:12).