After six years away, Mulder and Scully returned for 2008 movie Doggett and Reyes just didn't have the same chemistry as Mulder and Scully, and Mulder was almost entirely missing in action, appearing in only the two-part season finale.
As for Scully, she seemed to be increasingly in the background, as the Doggett and Reyes duo investigated cases. It appeared that creator Chris Carter might've been hoping Doggett and Reyes could lead The X-Files into a post Mulder and Scully era, but the fact that season 9's ratings sank like a stone is quite representative of the fan response to the show without its original stars at the forefront. In its original TV incarnation, The X-Files went out far from the top of the mountain.
There was a certain amount of buzz surrounding The X-Files: I Want to Believe going into the summer of 2008, as the project's story had been kept under wraps for quite some time. Unfortunately, once the movie released, its fortunes took a turn for the worse.
Why The X-Files: I Want to Believe Bombed at the Box Office
Opening in theaters on July 25, 2008, The X-Files: I Want to Believe opened at a measly fourth place domestically, earning $10.2 million. By the end of its stateside box office run, the film had earned only $21 million, and would add an additional $47.4 million internationally for a final worldwide total of $68.4 million. While few expected I Want to Believe to be a dominant box office hit, an entry in a popular franchise not even making $100 million worldwide is pretty terrible. I Want to Believe's only financial saving grace was its $30 million budget, although after marketing costs, its profit margin was still probably quite slim.
The biggest logical culprit for The X-Files: I Want to Believe's box office failure is the fact that it opened during the reign of David Duchovny and Gillian Anderson publicly blamed I Want to Believe's performance on The Dark Knight, and it makes sense. However, some other factors in play included poor reviews from critics, and the decision to make the film a standalone story, instead of wrapping up the dangling alien colonization arc.