I have now read the first three books in E.C Tubb's series "Dumarest of Terra". This week I finished Toyman, (#3). But this is not a book review.
Marc Miller himself named the Dumarest saga as a major influence on Traveller. So how does Traveller reflect Tubb's universe? There are several things. First there's the word Traveler, which the protagonist uses to describe himself.
Although Toyman all takes place on one world, there is discussion of High, Middle and Low passages. Since I've now had a PC die in Low berth, I appreciate more the gritty feel of the desperate who travel Low.
Earl Dumarest wears Mesh armor, and carries a big knife (a Blade). Some NPCs use lasers, alongside clubs and whips. Thus the uneven distribution of technology across space, and the inclusion of primitive weapons in the game.
The planet Toy (not really a joke) is an example of Government Type 1: Company/Corporation. Stockholders run Toy, and whoever has the most shares has the most influence. The guy with the biggest share is (again, not a joke) the Toymaster.