The Finality of Babylon’s Doom
21 Then a mighty angel picked up a boulder the size of a large millstone and threw it into the sea, and said:
“With such violence
the great city of Babylon will be thrown down,
never to be found again.
22 The music of harpists and musicians, pipers and
trumpeters,
will never be heard in you again.
No worker of any trade
will ever be found in you again. The sound of a millstone
will never be heard in you again.
23 The light of a lamp
will never shine in you again.
The voice of bridegroom and bride
will never be heard in you again.
Your merchants were the world’s important people.
By your magic spell all the nations were led astray.
24 In her was found the blood of prophets and of God’s holy people,
of all who have been slaughtered on the earth.”
With all due respect, what part of "never again" do you not understand?
Jerusalem post 70 A.D.:
Whomever mystery Babylon is remains a mystery. But, it is not Jerusalem!
Another reason mystery Babylon isn't or ever was Jerusalem, as if another reason is needed, is Christ will rule the entire world from Jerusalem once He establishes His Kingdom on Earth.
Even so, there are plenty more examples of why Jerusalem wasn't and will never be "mystery Babylon".
And finally, since it's STILL a mystery, this fact alone is a strong indicator the prophecy remains unfilled - for now.