You have to understand that there are two beasts involved here: (1) the “Seven-Headed Wild Beast,” and (2) an “image of the wild beast,” which is the bright-red, scarlet-colored beast that has seven heads and ten horns, the “eighth king, but springs from the seven,” and which supposedly represents the UN organization.
According to the WT’s unique eschatology, the seven heads of the worldwide political conglomerate will give their power to this “image” of the beast (the “eighth king,” or “scarlet-colored wild beast,” the UN), enabling it to turn on Babylon the Great through its political member nations. In reality, this seven-headed, scarlet-colored “image” of the seven-headed political wild beast are in effect really the same thing – the UN (“image”) is just a representation of the collective world powers/governments. It’s just a matter of semantics.
Although, of course, it’s rather ridiculous to predict that all the world’s governments will completely get rid of their religions. By far most of the world’s population is religious, and the USA itself, which is currently considered the greatest superpower, is by far comprised of Christian citizens. And what do all the US presidents say at the end of their speeches? . . . “And may God continue to bless America.” And what does it say on US currency? . . . “In God we trust.” So now matter what kind of Harry-Potter-like beasts anyone speaks of, I don’t think worldwide religion is going anywhere soon. (If anything, just more melding and morphing in the great human cauldron of childish nitwittery.)