Who is it that decides what is the "correct" on-going history of DS9?
Does the original franchise control the books and define a path to be followed?
The editor of a novel series is responsible for overseeing its overall direction and storyline, though the authors come up with most of the actual story ideas -- creating stuff is what they pay us to do, so why should they do it for us? An editor may have a loose plan for the direction of the series, while keeping that plan open to modification in response to the new ideas the authors come up with.
CBS, the studio that now owns Star Trek
, does not "control" or "define" the books. All that CBS Licensing does is vet the books to ensure that they stay consistent with Star Trek
canon (i.e. the TV shows and movies). Trek is just one of the licensed properties that CBS Licensing oversees, so it's not like they have time to do the creative work themselves (which is why they license book publishers to do it for them). As for the actual people who produced the various ST television shows, they've all moved on to other jobs (or, in some cases, died) and no longer have any responsibility for it.
Currently the only people actively overseeing new Star Trek
screen production are J.J. Abrams and his team at Bad Robot Productions, and they do oversee the tie-ins to the new movie universe (specifically the IDW comics and the young-adult Starfleet Academy
books) rather closely to ensure consistency. But they aren't involved in the creation of tie-in novels set in the "Prime" universe (i.e. the universe of every other Trek show and movie prior to 2009).