There are quite a few self-published books

in our local library system.
Most of them are family histories. Some of those are surprisingly well done. I think it may have something to do with the strong influence of the local genealogy society. There are several people there who are professional historians and they provide (paid) assistance. Our own family history (not written by me) could have done with some serious editing from one of these people. I did not like to argue with the cousin who put it together but there is a great deal in it I would have left out.
I think the same thing also applies to the other self-published books. Among other books there are a number of slim volumes - all by the same person. Although they are slim in themselves they need editing, serious editing. They would not have been cheap to produce. They have hard covers and nice photographs (taken by the author) on the front. It is a pity the contents are not as well composed as the photographs.
There are two historical novels written by someone I know. I also know why she could not get them published. Serious editing may just have made the first one good enough. It would not have saved the second. There are holes in the plots. There are errors in the history, far too many errors. I skimmed the first one out of curiosity. I skimmed the second one because the author asked me to read it. Skimming is a useful skill. The capacity to make diplomatic remarks wouldd be useful but I fear she knows I did not enjoy them. I did try to be polite.
I was given another one to look at yesterday. I made it to the end of the first page, handed it back to the librarian who gave it to me and said, "No thanks. I don't think I am interested."
"Oh but it is by a local author! They published it themselves! You really ought to read it."
Why should the fact the book was written and published by a local author make me like it? Thankfully our conversation was interrupted at that moment. There was no need to borrow the book or pretend I was interested.
There are local authors I like. There are three excellent histories in our library, all written by the same person. She is a professional historian. Her books have been edited and published by a reputable company. It shows.
In other places on the shelves there is fiction by local (state based) authors. It has also edited and published by mainstream publishers. I do not like all of it. I do not have to like all of it any more than I need to like all books which have been published.
There is one thing I do know however. If a book has been commercially published someone thought it was worth the economic risk. Even though some editing is better than others the book will have been edited.
The book I looked at yesterday had not been edited and it showed. I do not think they had even used the spell checker.