This is but another phrase signifying a great change: the whole verse is much the same with Isaiah 34:4. Literally these things were never yet fulfilled. It is a phrase signifying the fall of great and mighty men.
Related Commentaries of Revelation 6:13
Revelation 6:13
13 And the stars of heaven fell unto the earth, even as a fig tree casteth her untimely figs,c when she is shaken of a mighty wind.