What must happen before the present world system can be destroyed?
Before the present world system can be destroyed, the promoter of its misery and glitz must be defeated. Until he is defeated, these things cannot go down the tube. His defeat is the necessary prerequisite for the destruction of the present system and all it promotes.
Les explains that the current system has a promoter who is behind its misery and its glitz. He says it will not be until that promoter is defeated that all these things can go down the tube. In the surrounding context, Les connects this to the Second Coming: Jesus left from the Mount of Olives and will return to the Mount of Olives. Zechariah 14 describes the time when the LORD goes forth to fight against the Gentile nations that have come to destroy Israel. So the defeat of the promoter is tied to that future intervention, and only then can the present world system be destroyed.