Why do Star Trek reference books like these fail to sell well when Star Wars reference books sell so well?
It's important to note that, even when a "Star Wars" set of reference books sell
incredibly well, they can still send a publisher to the wall. Such was the case with Dorling Kindersley. They had built up a huge reputation for their "Visual Dictionaries" and "Incredible Cross-Section" books in the 80s and 90s, and then began doing did a range based on commercial tie-in franchises, such as the original "Star Wars" trilogy.
Then they won the exclusive license to do "Star Wars: Episode One: The Phantom Menace". Despite selling in very large numbers worldwide, the "Phantom Menace" versions of the "Visual Dictionary" and "Incredible Cross-Section" failed to make back Dorling Kindersley's investment. The original UK company faltered and its international warehouses were ordered to pulp the books because it was going to be too expensive to remainder them. (Down Under, all Australian schools were going to be given
free copies, rather than see the books go to waste - but only if the Australian government was willing to foot the postage bill; my boss at the Dept. worked out that that amount was, of course,
thousands of dollars, just to accept a warehouse of free books. So we had to refuse the offer, much to the publisher's annoyance.)
The "DK" brand, as it is now known, is more of an imprint, passed onto the new owners who, in recent years, have more carefully fostered the creation of other tie-in "Visual Dictionary"-type books, "Incredible Cross-Section" and "Essential Guide" reference books - and even more "Star Wars" volumes.
It was a severe lesson in how easily publishers can get burned, even on a best-seller. Similarly, Marvel Comics overspent on the license for "Star Trek" when they were doing the Marvel/Paramount lines. "TOS/TNG", "Early Voyages" and "Starfleet Academy" were very popular lines, and critically acclaimed, but not
popular enough to bring in sufficient profits to make the comics commercially viable.