A couple things harmon. First, on many new firearms the CDNN price is below the manufacturer's minimum advertised price, so if they were to advertise it they would lose that brand. A lose-lose proposition for all.
Second, some lawyer put the fear of god into CDNN regarding perception of online gun sales, which resulted in the long practice of not having any guns on their website. That has now changed. They now have an online-viewable version of their print catalog that includes guns for sale and some prices. AFAIK they still don't list handgun prices online, which is because some credit card processor decreed that would indicate illegal gun sales and they would lose CC processing if they did so, which would probably cut half their business. They had some serious problems with CC processing companies a few years ago, details of which were posted in their catalogs (I think late 2007, could be wrong) and I'm sure their current policy represents their judgment of the balance between customer friendliness and not getting run out of business by losing CC processing.
Third, a large share of their business is "liquidation" of out of production models, special editions that didn't sell well, etc. so by nature they frequently have small to very small lots of certain models that are permanently gone once sold.