A recent piece in the Guardian runs together two dangers for popular writers - celebrity and commercialization of their work through merchandising. Frankly, it's a load of bunk.
Very few writers are in any danger of becoming celebrities (I've never even heard of the Michael Faber mentioned as someone who 'doesn't enjoy the public figure thing'). Of course their fans will have heard of them, but they aren't in any danger of pushing TV and movie celebs out of the limelight. Even J K Rowling manages to keep a relatively low profile compared with the latest reality star's moment of glory.
As for the 'dangers' of commercialization, do me a favour. This is the literary old guard in their death throws. These are the people who could never really see books as a business, prefering to consider it 'art'. Publishing is commercial. Writers and publishers sell books; readers buy them. If you don't want to be commercial, give your writing away. It's easy to do on the internet. I'm doing it right now.
If readers are so enthusiastic they want to buy Harry Potter games or Golden Compass, erm, compasses, then why not? The very fact it was felt necessary to raise this as an issue verges on the pathetic.