“O how you have fallen from heaven, you shining one, son of the dawn! How you have been cut down to the earth, you who were disabling the nations!"
The fall of mighty Babylon vindicated Jehovah as the true God. Not only had he foretold that Babylon would serve as his punishing agent, wrecking all the earth, but God foretold the name of the man who would bring Babylon down, nearly two centuries before he was even born - naming Cyrus as the anointed of Jehovah, the liberator of God’s oppressed people; obviously, a type of Christ.
In conjunction with that, in the latter chapters of the same prophecy of Isaiah the repatriated Jews and company were said to have been ushered into a new heavens and new earth. To be sure, that expression is also used in the 2nd letter of Peter and in Revelation, both in reference to the system to come.
That being the case, the prophetic account of the fall of ancient Babylon did not merely vindicate God as a foreteller of future events, it led to the complete accomplishment of God’s overall purpose.