It's kind of too late now, though. Even if we somehow convinced every person on earth to never buy another Harry Potter anything ever again. She's already got her bag. That won't go away and she'd continue being a horrible person with the power of wealth.
Elon's wealth, on the other hand, exists almost entirely as a fiction of his businesses' value. He is much more susceptible to being taken down with them.
Somehow I doubt Rowling is losing any sleep over people she hates hating her back. That's why the streamer harassment campaign over the first game was a bad idea. It lost her no money and turned people to her side more often than gaining allies.