Some interesting articles recently on the biz of comics. First Journalista! points out that the website ICv2 recently estimated the entire Direct Market has retail sales of about $650 million last year (ICv2 is a pretty reliable source for numbers on comic book and graphic novel sales). Joey Manley writes "$650 million? Sorry. Iâ€™m just not that impressed." Compared to the total market for books it is a pretty small number.
Tom Spurgeon has a short post musing on the issues confronting the different facets of the comics-on-print publishing business. And at CBR, Todd Allen has a column which compares different sales channels for comics: Direct Market, Bookstores, Online Stories, Direct-To-Consumer.
Not a lot to add myself today except some speculation. I'd guess that a large percentage of the $650 million number for Direct Market retail sales is of the superhero genre. I'd find it hard to believe that there's much, if any, room for growth in that genre in comics as it's been so completely exploited by DC and Marvel over the years, so let's guess $500 million in sales as a ceiling for what is still often referred to as "mainstream" comic books. That's only one genre though – if publishers of comic books could develop other genres into at least $100 million plus categories, well, then you'd have a roadmap for the overall growth of comics. Start with popular genres in terms of sales of books and movies that have not been exploited by comics. You're not going to sell these new genre comics through the Direct Market (at least not primarily) but smart, innovative publishers could do it through a combination of bookstores and digital sales.