I just read an article in which Ursula Le Guin confirmed that she had been told by her publisher that her stories needed to be more like Harry Potter. Her response was that it was fear talking and that she wouldn't and couldn't write that way.
Lots of people have talked about the arrogance and stupidity of the publisher. But I'd like to look at it from the artist's side.
My first art teacher taught me to paint like her. Because in reality that's all we can teach someone. It is then up to the student to internalize and personalize that knowledge. In college it became painfully clear that I needed to understand the teacher to get good marks. In other words - paint like them. And that is probably the only way to experience different techniques and view points from which you can create your own toolbox. No one broke that down for me at the time and I grumbled mightily at not being able to just keep plodding along in my own artistic rut.
Writers are told to read a lot. And in workshops we are taught how successful writers write. Again it is up to us to see what makes sense and what fits in our toolbox.
But to tell an established writer that she needs to adopt someone else's style is flat out wrong. I'm a big fan of Ursula Le Guin. She's a wonderful storyteller. I am also a fan of JK Rowling. But there couldn't be two more different writers. And that's wonderful. If Ms. Le Guin started writing Harry Potter knock-offs her fanbase would revolt. That isn't the type of story she writes. And she said so - more power to her.
I think the fallacy here is that we fans don't necessarily want more Harry Potter clones, we want wonderful, big stories with great heart. I think most writers, who are also readers, already know that. And I think that eventually, the market will prove that out.