Given a pre-trib rapture assumption,
there will be a time between when all the saved folks are yanked away, and when the first tribulation era Christian gets saved.
The “restrainer” will be gone for a period of time.
Plus, the chaos of all the missing people will indeed cause massive hardship for those left behind.
I am not particularly fond of pre-trib... or at least the way most folks consider it - The Bible CLEARLY says that it is at the sound of the 7th trumpet that the rapture occurs. Nice to miss out on the bowls and vials, and all, but we should know to look for the trumpets (and the thunders) cuz we are gonna see that much at the least. And if one reads the results of those trumpet signs, one could dare to say that there is a bunch of 'the tribulation' going on there. And IF Christians are all taken up before then, who exactly are the martyrs who are prophesied?
The “restrainer” will be gone for a period of time.
2Th 2:7 For the mystery of iniquity doth already work: only he who now letteth [will let], until he be taken out of the way. (KJV)
Actually, I think you had better look at 2 Thess 2 more closely... And there is no passage which identifies the 'restrainer' as the Spirit. That is nothing but an ill conceived assumption.
As I asserted earlier, the Spirit is the primary force leading folks to salvation, and guidance thereafter - If there are to be tribulation saints, and saved survivors (which there ARE), it is inherent in the process that the Spirit is present.