The development of the Third Imperium, or more recently Charted Space, literally began the concept of a setting arc in RPGs. When Traveller was first written in the 70s, the idea of a cohesive setting for an RPG hadn't been invented. The Third Imperium Was cobbled together after the release of Star Wars because everyone thought there should be a big "capital E" empire. Even the idea of different alien species was something that came up later on in the setting as it developed.

The article there does not go much into this, but I'm reminded that many people really disliked the later timeline development of the Traveller setting; and the Interstellar Wars timeline was welcome because it was set earlier, and the Mongoose reboot takes the timeline in a different direction. So I've gathered, anyway.

Can anyone point me to contemporary discussions of why the Traveller canonical timeline was so unpopular?