To further reinforce what Grognardia says about Traveller here. Here is this article from a long time fan site - Freelance Traveller which speaks about the pre-imperium days of Traveller when campaign were one or two sectors in size and empires spanned dozens of worlds.
Thanks to Far Future Enterprise you can still buy the original and see what everybody is talking about. Thanks to Mongoose Publishing we have a near clone that has been released under the OGL. So today anybody can pursue their own vision of what Traveller is. Although to be fair Marc Miller (and Mongoose) are pretty liberal about the fan community is allowed to do as long as a few simple conditions are met.
Today many are debating whether the dominance of the Third Imperium setting was good for Traveller or not. At the time nobody really had the idea of classic gaming. It wasn't just D&D that was afflicted with the idea that the next edition had to be bigger and better as succession of Traveller, Mega-Traveller, and Traveller New Era showed. The classic version of Traveller ceased to be supported when Mega Traveller came out. Afterwards the only thing that united the fanbase was the Third Imperium.
But since the release of the reprints and the OGL version of Mongoose Traveller. Now we can have it both ways. The Traveller market can cater to fans of the system and too fans of the Third Imperium. And because the Third Imperium grew out of the assumptions of the classic Traveller rules, both can benefit from the work of each other.
If there is an ideal situation for a revival of a classic game Traveller has it right now.
34 minutes ago