Death of the Author doesn’t really work when the author is still alive, profiting off the work,

Actually, it makes it more striking. What you're doing there is conflating art and art reception with economics and economical relations. In purely artistic terms yes she's deader than dead because anything she says about anything about her work will be disregarded if fans don't vibe with it. Usually, while still alive, artists at least have some influence on the interpretation of their works, she doesn't. Not because she's physically dead, but because fans have declared her dead to them.