This prophecy looks to the distant future from Isaiah's point of view. When it was written, Judah was still unconquered and Babylon was a threatening power. But Isaiah was given a vision through time's telescope. The empire that would lead Judah captive and wipe out Jerusalem would itself fall under God's judgment, even though it had not risen to superpower status yet! The mighty Babylon would fall, and none of the gods of the Babylonians would ever save them from this fate decreed by God a lifetime before these events occurred.
There is again a sad note on the idol-making ability of the human heart. All the idols in which the Babylonians trusted would be ruined. Their gods would be shattered on the ground. The things we place above God and the affections we have held instead of God must all fall. They are doomed. Only God can be what the heart longs for and needs.
There is a warning here. God will take our idols down. They will break and shatter before His sovereignty. We cannot have any god before Him. Even those without God will see their object of trust come to nothing. Worship is a serious mater and not a thing to trifle with. And that is why idols are smashed.