Beyer's books sell because she is incredibly talented and writes Voyager better than the television writers ever did.
And Christie Golden's VOY books also
sold extremely well - that's why she got the Relaunch gig - with a few of the Janeway fans even saying that Golden was the only Pocket author they liked.
So has there been a loss for the franchise or a win? Are you going to try to please just VOY fans (or just Janeway fans), or the more general ST fans? Seems to me the more general ST readers prefer Beyer to Golden.