Have you ever read past 1st Thes 4? The subject doesn't change. Everyone is so quick to post 4:17 as proving a rapture and never read past into 5 where the subject continues. There were no chapters in the manuscripts. These are letters. If you had read past 4 into chapter 5, you would see that Paul names the very event of 1st Thes 4:17 -the day of the Lord. That takes the mystery out of it. It's not a secret rapture. If you read all of the verses together to not lose context you would see that he only comes like a thief to those not watching for the signs and seasons. And if you had read further into 2nd Thess you would see that he had to tell them not to be confused or shaken in mind that the day of Christ was at hand (iminent) it wasn't. Certain events have to unfold. One being the son of perdition sitting on the throne proclaiming to be God. I used to believe in a pretrib rapture but it's not biblical. And tribulation and wrath or not the same thing.
Christ will return at the 7th trump and not a moment sooner. Many things will unfold before that happens, including a falling away/apostasy -meaning many will depart from the truth. We have to heed the warnings by both Christ and Paul about deception. And it it happens to one generation, they have to have full gospel armour on and be able to stand, having done all to stand. (in that evil day) Christ states those that endure to the end, the same will be saved.
Part of Paul's second letter to the Thessalonians was to address their confusion on "our gathering back to Christ". He states it will not happen....until certain things unfold. He said don't even be confused by his letter (1st Thess) The subject is when Christ returns. And if a pretrib rapture were possible Paul would have said something to them. They were waiting on the return of Christ as well like many are today so why would Paul bypass a pretrib rapture if it were true?? Why the warning? That's because it's not true. But people would rather believe a lie than accept the love of the truth.
The reason he was comforting people in 1st Thess 4 was because he was talking about their dead loved ones. That was the original subject.
In 2nd Thess why wouldn't Paul have stated during their confusion, don't worry Christians will be taken away? Instead he states don't be deceived by any means. Sadly that deception is off the charts even today after Christ and Paul, later John laying it all out there.