Maybe. On the other hand, I suspect that, precisely because he is a popular (at least by genre standards) author, he probably also gets some benefit from the publisher in terms of sales, promotion, etc. I've heard from a number of sources that one of the issues with going to a traditional publisher for a new author today is that you have all the publisher overhead while not getting much of an advance or much in the way of marketing and promotional support.

But I don't know how the relative economics work for an established author like Charlie. Empirically, most known authors seem content to stay with publishers so I'm guessing it makes economic sense for them. But I don't really know.