Publishing: How does the "mix" affect writers?

Here’s a question for publishers and literary agents.  This morning, NBC featured yet another book tour interview.  This time it was a non-fiction (I’m assuming) tell-all from a former Miss California and gay-basher who, by the way did make a ….sex….tape.  Oh No! Not that!  Maybe she wrote it, maybe it was ghost written after her agent explained the money to be made, who knows?  It raised a question for me, immediately. 

I assume that publishers work with a finite number of books they can produce in any given year.  The number must be based upon market conditions and costs.  I do know that re-prints of existing books tend to be a hard decision if they’re not selling well — that makes sense, financially.  I also know that if a publisher produces both non-fiction and fiction, the mix proportion is probably determined in accounting ultimately.  They probably leave a certain amount of wiggle room, to take advantage of instant opportunities that come up — like this new hardcover tell-all that the world clearly needed (insert sarcasm here). 

You can’t fault the publisher for the amazing appetite for garbage the market seems to exhibit.  After all, BIG publishing is not a non-profit organization. Some smaller ones are, much to their chagrin, and not because they don’t work at it.  My heart goes out to them, as they really are trying to keep the art of literature alive.

My question concerns the impact to new authors and unpublished authors.  If there is a fixed number of books that can be published any year, doesn’t each book produced to take advantage of a perceived short-lived celebrity — like this new hard cover — reduce the chances for a publisher assigning a slot to a new author?

Please correct me if I’m wrong, but looking at the industry from the weary eyes of running a small business, it seems that the only answer is that for every 15-minute celebrity tell-all, one less real work of important writing must be overlooked.  With mainstream publishing still pounding the table, insisting that they are the "gatekeepers" of quality and good taste, the field seems to be getting mored tilted all the time against new authors, especially fiction writers that only write well.  Maybe we should all do sex tapes?

I’m tired of the old, tired publishing fable is that they will gladly publish a new writer’s work…if it "good enough".  Market conditions are part of the mix, and given what I’ve read and heard about, the definition of "good" changes constantly.

Am I wrong?