I recently had a question from an author/publisher who was essentially thinking that all she had to do to get "distribution" was have her book listed in Books in Print - a Bowker service that goes along with your ISBN. She is planning to have her book printed digitally and couldn’t understand why using Lightning Source as the printer was so important to her due to their connection with Ingram (Lightning is part of the Ingram Book Group and provides all publishers who print with them access to Ingram to supply the book trade). This is the response I gave her.
If I’m reading your post correctly, I think we are talking about apples and oranges.
Yes, you are correct that the retail systems get their information from the BIP database - including Ingram. But it is just that - a database of information about who the publisher is, who distributes the book, what size and type of book, etc.
So let’s think this through for a moment. Your book is listed in BIP with you as the publisher and no distributors because your book is printed on demand by X Printer (no one has inventory). So let’s say that the retail store has lots of time on their hands and they really want to get your book for their customer (an unlikely scenario - they are more likely to say "we don’t handle it" because they can’t get it easily through their normal channels of distribution).
What do they do? Where do they go? Without the Ingram connection as a wholesaler, the only choice is to call you directly - the publisher listed in BIP. How will you get them the book? They won’t (in all likelihood) buy directly from you as you aren’t set up in their system as a "vendor." They want to buy from one of their established sources - their own warehouse - or perhaps Ingram. So you have probably lost the sale. Does that make sense?
You must have some sort of "trade distribution" in order to have "trade sales" - just being listed in a database does not give book sellers "access" to your book - a place to source it from. That is why the Ingram connection is so valuable.
If you don’t print through LSI as an on demand printer, then you will have to strike your own deal with someone like Baker & Taylor to handle your book if you want it available to the trade. You would then have it printed by your on demand printer to fill their orders and arrange to have the books shipped to your wholesaler (in this example Baker & Taylor). They require a 55% discount from list, plus you pay shipping. With your cost structure, can you afford to do this with your on demand printer? Printing with Lightning makes it simple and affordable.