I am not in this dog fight. Lol.
And I'm not calling Butler Books because I have zero interest in it.
Anyway, there are 3 ways to officially get a book published.
Traditional Publishing... A publisher believes your book will do well and make money, so they publish it at zero cost to you. They do everything but write the book. Authors end up getting anywhere between 5% and 15% royalties (for life) on each book that sells, based on the retail price of the book and whether it's a hardcover or softcover.
Self Publishing... The author publishes the book and works with a print-on-demand company. The author can officially get a business license and name their publishing company "Bebob" (Bob Henning), or "Billiards Press" (Phil Capelle), or "Bookymonster" (me

). Authors typically get 40% to 80% royalties for each book that sells, depending on if it sells directly through the printing company or through one of book sellers the printer's worldwide marketing distribution network, which included about any bookstore chain, along with Walmart, Amazon, etc...
Author-Funded Publishing...Authors pay publishing companies or printing companies to print X amount of books for X amount of dollars. Books are printed and distributed to the author, who then sells them in order to get their investment back and make whatever profit is available. This is what Stan did with Butler Publishing. It's also what Mark Wilson did with Blue Book Publications.
Almost any pool and billiards book you've seen, or will see, is NOT published by a traditional publishing company. There's just not much of a market in pool and billiards to fancy traditional publishers.