That's just silly. Folks are SAVED during the tribulation. How can that be if the Spirit is gone?
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.