I have heard this objection to prewrath on occasion. It is easily answered:
Darrin Ball has a good response:
I agree with Trond. It’s like asking, “Where are the 144,000 in the Olivet Discourse?” Not every element is present in every eschatology passage. The trumpet is present in Matthew 24:31, but nowhere in Mark 13, but it is in I Cor. 15:52 & I Thess. 4:16. At the cosmic signs in Matthew 24:29-30 and Revelation 6:12-17 the nations are in terror in both passages. They see Him coming in Matthew 24:30, and in Revelation 6:16 they ask to be hidden from the face of Him who sits on the throne. Both passages express some reality that He is now visible.
As far as a trumpet, it’s not at the sixth seal, but it’s not in Mark 13 either. Would we say Mark omitted it because it doesn’t happen in his version? Or would we say that each chronology gives different details and we can overlap them based on a majority of similarities in the text?
The gathering should be seen in Revelation 7:9-17, when we see a group of people from all nations and languages at the throne of God. They are experiencing the resurrection blessings of Isaiah 25:8, see I Corinthians 15:54 and Revelation 7:17. I don’t see a gathering at the seventh trumpet, unless I missed something.