Wow. Never heard of this Cassie Claire before, but a little investigation showed to me that she is a big shot. Anyway, while I understand the reasons why one would use plagiarism to create fanfiction I think to me they miss the whole point about writing. The only praise you get as a fanfiction writer is feedback, and the best feedback is on a line or idea or plot that you yourself have made up. Of course creating and satisfying a huge fanbase is also great, but the pleasure of writing needs to come from writing itself.

I think that even with all her billions and fame Mr Rowling likes the
writing process still the most.

O, and I think that you, Liz, need to get your own Wikipedia entry ;)