I stumbled across a copy of Jeff Levine's old Destroy All Comics zine from 1996 and was re-reading a classic interview with Drawn & Quarterly Publisher Chris Oliveros, which contained the following exchange that was interesting to me insofar as it underscored just how much has changed in the world of comics in a little over a decade: 

Q: Do you think it's possible that there could be more work in the future where the artist could sit and draw for two years, and release the entire story, or do you think just the way the industry is set up, and with history on the side of the periodical nature of comics...

Oliveros: I think the periodical approach is a good thing. In order for comics to be released in book form, where an author would take two or three or five years to complete this novel, the medium would have to attain this sort of popularity you have in general fiction, where you have fifty or a hundred thousand readers, and your best-sellers have five hundred thousand readers, where because you have this guaranteed income, you can get this advance from a publisher of, I don't know fifty or one hundred thousand dollars, and then you can afford to work on just your own project for a couple years. That obviously will never come to be in comics, so I think, for better or worse we're left with this set-up we have here, where the work is gradually being serialized, which in turn allows the author to collect a royalty on those issues. Without that, comics just wouldn't exist. Whether you like it or not, it allows these works to exist, and it allows the author to make some kind of living while the story is being produced. 

Mind you, I would have agreed entirely with Oliveros at the time. And in a lot of ways, I think it still underscores a fundamental challenge facing publishers vis a vis the increasing inevitability of graphic novels supplanting periodicals as the chosen format.