Ahem.Revelation 13 does not say every person on earth takes the mark.
It says the beast causes all to receive the mark, but the chapter itself distinguishes between those who worship the beast and those whose names are written in the Book of Life.
More importantly, if every believer is either martyred or takes the mark before Christ returns, then you still have to explain passages that describe living believers at His coming.
The problem is that you're taking:
The beast overcomes the saints.
Many saints are martyred.
A great multitude appears in heaven.
and then adding:
Therefore every believer is dead before Christ returns.
That last step is not actually stated in the text.
Revelation certainly teaches massive persecution and martyrdom.
What it does not explicitly say is, "No believer remains alive on earth when Christ returns."
That's why posttribbers keep pointing back to Matthew 24:29-31.
Jesus explicitly places the gathering of His elect after the tribulation.
So if Revelation 13 is interpreted to mean there are no believers left to gather, then that interpretation has to be reconciled with Jesus' own stated sequence.
The debate is not over whether there is martyrdom.
The debate is whether martyrdom equals total extinction of all believers before Christ's return.
The text never explicitly says that.
It says ALL TAKE THE MARK NOT IN THE BOOK.
Simple fact.
Now, what happens when they refuse? ???
Ahem....they die for their their faith.
So you are pressed to rewrite "All", and claim you guys are not martyred.
Even though we can SEE AN INNUMERABLE NUMBER IN HEAVEN THAT CAME OUT OF THE TRIB.
Hello....They ARE MARTYRED FOR REFUSING THE MARK.
You really need to connect the dots.
They ARE MARTYRS WITH DIRTY ROBES.
The foolish virgins.
Carnal secular believers with dirty robes, Left behind after the pretrib rapture.