Perhaps I shouldn't have been surprised. It took my website platform team (Librios), along with the printers (Clays of Suffolk), over a year to sort out the issues for The Unbelievable Hamlet Discovery. To begin with, there's a design issue to be solved. At the end of the day, the book has to look like any other printed book you'd see in a bookshop. So it has to go through the same stages of design and copy-editing and proof-reading as any other book submitted to a publisher. It has to have its ISBNs (plural, note, as printed book and ebook have to have different identifiers). Just because we (Hilary and I) are the publishers doesn't mean we can cut any corners. Fortunately we both have had plenty of editorial and design experience over the years. But it still needed a final look-through by a professional designer. And we learned an important fact: Clays are unable to PoD if a book is less than 80 pages.
A bigger problem, which took ages to sort out, is how to handle the postage. Once the book is given a price, the story isn't over. This is the biggest difference with buying a book at your local bookstore. The purchaser is typically going to buy just one copy, but the order can come in from any part of the world. This is what makes PoD so attractive to authors: their readership is worldwide. But how is the printer going to handle an order that comes in from the UK, or Germany, or Africa, or the USA...? The postage rates vary greatly. So all this has to be worked out so that orders can be processed automatically. Along with the further complications of VAT (where applicable).
Anyway, it's all sorted now, so if you order a copy, at www.davidcrystal.com, and pay via Paypal, it should arrive on your doorstep a couple of working days later. And those who prefer an e-copy will be able to do so directly, at the same site. (Here too there have been delays, as there are different design issues that have to be addressed.)
Actually, I would far rather have had the book published by a conventional publisher and sold in a conventional bookshop. I am very conscious of the need for authors to support the book-trade. So I would never self-publish without going down the usual publishing routes. I offered the Hamlet manuscript to two of my usual publishers and they turned it down - amazing, really, considering the significance of the discovery, but there we are. Similarly, when Hilary self-published her first children's novel, The Memors, it was only after we had explored possible publication with three houses. The only other books we self-publish are those in my backlist that are out-of-print, and where people are still interested in them.
Having said all that, we do find self-publishing an enormously exciting experience. We like being in control of all aspects of book production. Maybe, in another life, we would have been a publisher.