In the PoT materials, it describes that the Guild is sizable but pretty loosely organized.
Their primary goal is profit motive without boundaries, not evil for the sake of being evil - notably, it describes slaving as a profitable thing for many Guild captains. However, the Guild won't be spiteful or cruel if means cutting into their bottom line. They're amoral, not immoral.
The Guild has some overarching goals like control of all starships, control of the education necessary to operate starships (especially astrogation), and keeping worlds isolated from each other. They're pretty loose goals, driven by what the Guild sees as best for it - most captains go along with it because it enhances their own profitability. A lot of Free Traders are impressed into joining the Guild unwillingly, and the materials hint that there's a significant minority of original Guild captains who don't really like the cutthroat business model of the Guild as well. Guild captains out in space compete with each other for markets and profits - there appears to be no cartel within the Guild that controls who sells what where and when.
Here's my game experience as a GM: The Guild doesn't play well together - as an association purely for profit, most Guild members don't really have much stake in the Guild. Guild members are more likely to see one of their fellow captains tangling with the players as an opportunity to get rid of competition than a threat to them all.
Given the players often have a 3-6 TL advantage in fights against the forces of TEDs, they tend to walk all over TEDs. RC standard ground force TL is 12 while a lot of TEDs are hanging around the TL 8 to 9 range, in space the difference is greater. My players tended not to hoard tons of equipment, but they tended to carry the best they could find and are often pushing TL14-15. In situations like that, I find the local TL8 TEDs pretty much don't stand a chance. Smart players (which mine are for the most part) go where they want, they rarely stand still, and always attack with Electronic Warfare superiority. My players (and I) aren't Marc Miller - we simply don't find stomping a World War II era panzer division with TL14 battledress to be any fun and the Guild simply doesn't have the products necessary to really train and arm TEDs to a level where they can provide interesting high TL fights (if such a thing is really even possible the way Traveller TLs are set up).
The real interesting parts of my RC campaign occurred when the more moderate factions of the Guild saw the direction the wind was blowing and decided to get out early and started defecting to the RC when the players managed to convince Maggart to offer an amnesty-and-probation program. So the players had to play "cloak-and-dagger" keeping an eye on a bunch of former Guild captains, which they knew contained infiltrators (but they didn't know who), others who were being approached by less ethical factions in the RC as captains they knew would be "willing to do what's necessary", and so on. (of course, in my campaign, then the Vampire Fleets showed up.)
Conclusion: I think the line about deep space jumps really were highlighting the strengths of the Guild. Without a monopoly on this information, they're really sort of a weak faction. Eventually, I think GDW wanted the RC to face the real threats which they were more suited - the Guild could never field an army or a navy and while the Guild could make like difficult for the RC, they ultimately couldn't ever stop the RC from going where they wanted to, when they wanted to. The RC was laying down all these battalion troop transports and "blue space" naval vessels and needed an enemy like Solee that was more suited to such a military.