There's plenty of books that have revisions, but yes, the first version does not physically change. Then again, other than collectors, I don't know many people that have multiple books of each revision/reprint of the same book. To your point, it's not like you can read a book, go to bed, and then wake up to a modified book. However, you could damage your book and go to have it replaced with a different version. Say you loan/give your copy away knowing you can get a new one easier than having your recipient get a copy for themselves. Your new one could be different. It's happened to me