I think I see where the disconnect is coming from. You are discussing "the game" as being the rules and all the attendant Adventures and Supplements that were published along with the rules.
For me Traveller is a set of light, flexible, and brilliantly interlocking rules that allow a Referee to make ruling on the fly but always connected to the rules element in play (characteristics, skills, DMs, Throw Values, and more) that keep the game from becoming arbitrary. Additionally, the rules come with a toolkit for building your own setting and creating, as a Referee, lots of cool enigmas, mysteries, SF developed societies and so on. And of course all those bottom slots in Tech Level table are waiting to be filled in by the Referee. And so, by all of this, I mean Traveller Books 1-3.
If one defines Traveller as you do -- with the setting of the Third Imperium (a strangely not-very-SF place) and the specific adventures you mention, then sure, yes, one could see it as "the game as is."
But that's not my game "as is" at all.
For the first two years after Traveller was published there was no Third Imperium, no adventures. Everyone was making up their own settings, their own kinds of adventures. They had to. And it wasn't shaped by the Third Imperium at all, or the adventures that would later be published -- because those things simply did not exist yet. They were working off the pulp adventure stories that Miller had read and inspired the game. Those aren't at all what you are describing (and I'm kind of boggled you decided to ignore all the references I put in my previous post -- but it's the Internet, so whatever)...
So your Traveller is literally different than my Traveller. I'm perfectly willing to believe it is as limited and fixed as you claim. But it isn't what Traveller is. It is what you are choosing to limit Traveller to.