Shows often continue after they've lost their purpose, and fans tend to stick around to justify the hours they've already invested in a series.
There used to be a time when television was considered inferior to the cinematic experience. However, storytelling on TV has entered a golden age that’s responsible for some of the best narratives and characters of recent decades.
Based on CBR's list, The X-Files is amongst these declining shows. While explaining that the series was ruined because its mystery was giving too many answers, the following was stated:
The X-Files has played a pivotal role in the development of mainstream genre storytelling and had a lengthy run of more than 200 episodes. The show maintained a surprising level of quality when it came to its episodic monster-of-the-week stories. However, the increasingly convoluted and changing alien conspiracy mythology exhausted viewers. The loss of David Duchovny during The X-Files' later seasons didn’t help and many viewers returned for the finale and revival just to learn what was going on.