No, not even that author that is taking a really long time to finish that series you like
Your personal investment in the story isn’t equivalent to them owing you anything. You aren’t funding their future books. You aren’t their editor or their agent or their publisher. They aren’t answering to you, no not even if you’ve read all their books several time and have multiple copies and can name every character and their backstory. You aren’t their boss.
You can be upset at not having a finished series, but you aren’t owed it. To quote Neil Gaiman, writers “aren’t your bitch” and complaining to them about how long its taking for them to write a book or saying that they’re going to die before they finish is really gross and people who do this need to stop