In TV there is a watershed moment. Before sopranos and after sopranos.
The shows that came before were specced to the particularities of broadcast television. Season length, episode lengths, budget, guest appearances, were all determined by the details of how broadcast television was organized in the late twentieth century, with seasons and sweep weeks and all that crap.
HBO was the first TV producer to bin all of that, and enable TV to reach its creative potential.
X files was a very cool show, but its late 20th century broadcast pedigree is on full display.