I'll take your Lost words with trepidation but I disagree that the X-Files writers didn't write themselves into a corner. By the time "The Sixth Extinction" rolled around they were awkwardly trying to shoe in Biblical myths and "biogenesis" and Mulder possibly being Cigarette Smoking Man's son and spaceships in Africa and something about Scully's baby having mystical powers and screw it. I couldn't pass a test on it anyway.
They actually threw out most of the mythology for the last two seasons when Robert Patrick entered the cast, and just did mostly standalones, and then brought Duchovny back for the big two hour finale which was mostly a clip show, Mulder and Scully on trial, and a final meeting with the Cigarette Smoking Man where he dies (but I guess these new episodes lamely brought him back). It wasn't a great final episode but it wasn't the worst either; it did end the show's mythology (at the time) on a who-gives-a-crap arbitrary note: everything led up to the big reveal of....aliens colonizing Earth in 2012, but hey, Mulder and Scully are in each others' arms!!
Then, they did a worthless second movie that had nothing to do with the mytharc at all and I can't even remember what it was about, in spite of watching it twice to be sure.