There is a difference in books that 1) have never been copyrighted, or their copyrights have expired (so the book is in the public domain) and 2) books which have been copyrighted, but are "open access."
With the first kind of book, I don't think that there are any limitations as to what you can do with them. People and companies are all of the time reproducing them, editing and reproducing them, etc. and charging for them many times. All legit.
Open access (there is some ambiguity in the terms, but generally they indicate that the work--ebook, digital recording, whatever--is free), however is very different. All open access books, if I'm not mistaken, have valid licenses. None of those licenses, as far as I am aware, let you do whatever you want to with them--there are always one or more restrictions on how you can use them. I don't know if there is a limit on how many years that the owner can keep the license--it may be like copyrighted books, and after a particular amount of time they become "fair game" for anyone to do with them what they like.
As I mentioned, open access books are licensed under one kind of Creative Commons license or another. The best single-webpage description/explanation of the differences between these licenses is
here.