Wube Software announced that they will be releasing an expansion pack for Factorio and why they didn't go several other ways that were seemingly open to them.
Factorio has been around for over eight years now and in that time the game has received a pile of updates. In fact, the team had 411 public releases, ranging from minor fixes to new content and it seems like it's time to finally move to something else.
That something else turned out to be an expansion pack but the thought process wasn't as simple as just deciding to do it. According to the devs' blog post , they were pondering which of the four ways to go - keep going with free updates forever, create a sequel, push out smaller updates or get one big expansion pack.
The problem with the free updates forever path was that the game doesn't have as much traffic as the likes of Minecraft or Terraria so it probably wouldn't be sustainable in the future.
Ideas about Factorio 2 fell through because that would require bringing changes that are considerable enough to make it an actual new game which is not what Wube are going for.
They are also not fans of small DLC packs that usually don't carry the game they are released for so that idea seems to have quickly been discarded.
Finally, there was the idea of one big expansion which took off. Unfortunately, it's still too early to talk about what the expansion will feature or when it might arrive but it seems to be at least one year away from release.