The passage in Isaiah is about the new heaven and new earth. The sin-tainted world will be no more.
And no, I have no compulsion or requirement to humbly try to lead someone to Christ who has no interest in it, and is actively hostile to the truth. God wins no matter what you or anyone says, so it's ultimately not going to matter to me one way or another. There are passages that suggest people in the lake of fire will actively still shake their fists at God... All while being continually tortured with no end.
This "little lamb" would agree with your position, but then we'd both be wrong.