By now, we all know the long twisted history of the Alien franchise. From the greatness of the first two films to the mediocrity of the Alien:Resurrection to the absolute terrible notion of Alien vs. Predator, the series has seen much better days. Although Prometheus got somewhat back to the range of his original ideas on the Xenomorph, that movie left a bad taste in the mouths of many viewers that had problems with the strange pacing, massive plot holes, and weird motivations for its characters.
Now, Ridley Scott says he's not closing the series, but wants to keep it going as long as possible. Instead of concluding the saga, he wants to continue it with another three films, with Covenant bridging the gap between Prometheus and the original Alien. By saying "I'm not going to close it down again. No way.", we're assuming there are long term plans for the series well beyond what he might be able to complete himself.
No matter what, if the quality of Covenant gets closer to the original films in the series, we could be seeing a full revitalization of this entire franchise. It's good to know that Ridley Scott is back at the helm of this project and has a major focus on regaining the glory days of human on alien contact.