The physical city of Jerusalem can't be Mystery Babylon in my opinion... Doesn't fit scripture...
Revelation is about events "at hand" when it was written, not 2000 years later. Jerusalem was God's bride, adorned in his blessings befitting his bride. And the temple was adorned in gold and other precious things. The church, represented by the new Jerusalem, has been God's bride for the last 2000 years.
The riches and trade related to the great whore are spiritual in nature, not literal. E.g. marine marchants shows there to be a sea, contrast that to the new heavens and the new earth where there is no more sea.