By now you've seen how difficult it is to try to analyze and systematize the content of apocalyptic writing. John is describing a vision, and in so doing is attempting to describe the indescribable. Scores of well-meaning attempts have been made over the years to tell us what John "really meant", but all such efforts should be taken with more than a grain of salt. Especially if the would-be interpreter is dogmatic about his interpretation!
This is why it's refreshing from time to time in Revelation to come across material that hints at the purpose of the vision. Look at verses 20 and 21. These two sentences follow a description of two of the three remaining trumpet-disasters. The fifth trumpet precedes a fallen star unlocking "the shaft of the Abyss", out of which a dense cloud of smoke produces a plague of tormenting locusts (vv.1-11). The sixth trumpet releases a supernatural army of 200 million who destroy a third of mankind. What's the point of these cataclysmic horrors?
Apparently repentance is the point. Verses 20 and 21 tell us that the "work of [mankind's] hands" are sufficient to bring heaven's wrath upon the earth. That "work" is idolatry, murder, occultism, and sexual immorality. The scope of the disasters shows how enraged God is at sin. Were it not for the gracious work of Christ, mankind would have been destroyed long ago. That's why we should repent of all sin now — while there is yet time.