I suspect that they knew, toward the end, that it was going downhill in a hurry. The episodes just didn't carry the same air of "authenticity", which made the first few seasons so dramatic, and close to believable
The Xfiles was about Aliens, crime connections, and the Government covering it all up. then It started getting more and more "supernatural" orientated towards the paranormal route.



I have a similar "I Want To Believe" poster on My
wall! anyway I believe some of the stories were based off true happenings! just My two cents