Nigel Mitchell said:
My perspective is that if it's written well enough, the reader should never lose interest. My book should always be at the back of their mind, leaving them wondering, "I wonder what happens next?" If the reader goes, "Well, it's taking too long so never mind" then I never really grabbed them in the first place.
Sorry, but no. Unless your book is the only one someone ever reads, it is unlikely to stay with a reader forever in that much detail. There are a number of books that I have thoroughly enjoyed over the years - why else would I keep reading? - and if all of them set up permanent residence in my head, there would be no room for anything else. Yes, there are certain books that last longer than others. Yes, there are certain characters that resonate with you on a different level. But these are few and far between, and you cannot expect every reader to respond this way regardless of how well the book is written.
People have busy, distraction-filled lives. If I regularly checked all the authors I enjoy reading for new releases, I would never get anything else done! You cannot expect people to wait on your doorstep for you to produce something new. I won't lose interest in the story if I liked it, but I may lose interest in coming back month after month to check if there is a new book out yet. That said, I am also hesitant to sign up to a mailing list and open myself up to a litany of irrelevant information from every writer that I happen to have enjoyed - but that's just me. If there was a service that let me plug in authors' names, which then sent me a notification whenever something new by one of them was published, that would be ideal. (If it exists, someone tell me where!)
What is more important than the speed of production is the method of getting the reader back. Unless you have a huge back catalogue (and often even then), your readers
are going to read something else in between your books, no matter how dedicated they are to you. The key - and the challenge - is in letting them know when you next have something for them to read. If you have impressed them the first time, they will come back when/if they hear your next piece is out.