We've all sung the praises of the Star Trek Encyclopedia on this site, and look how it did.
As far as I know, the first two editions of the "ST Encyclopedia sold well enough, or else Simon & Schuster wouldn't have kept making new editions. But the first one came out when there were still lots (and lots) of casual viewers of TNG. People who had a strong, but passing, interest in Trek, plus people buying the book for relatives and friends they knew were avid fans and were otherwise hard to buy for.
The third edition was
much harder to sell because TNG and DS9 were already off the radar of those casual fans, so the Simon & Schuster number-crunchers decided it would be unprofitable to redesign the whole text, added the new material as a supplement at the back, and buyers resisted. Many TNG-only fans didn't need extra pages that added mainly new DS9 episodes to the book.
These days, a new edition in hardcopy would be a huge undertaking: more VOY, plus ENT and JJ movies to be added, and many people are happier with the convenience of online information. Which is
free - and updated daily.
The highest hurdle for any crossover story involving characters owned by two different production houses is usually settling on what $$$ outlay is required.
Can't say why the Encyclopedia didn't sell well, but right now comics appear to be on a lot of people's radar, so they stand a good chance of doing well.
Are they?
The Trek comics from IDW are often rather hard to find, and many have been scathingly reviewed. AFAIK, they are not selling the kinds of numbers as the Marvel and DC versions of the 80s.