The webcomic Goats has been running for 13 years, and creator Jonathan Rosenberg is about two years away from the big climax of the story, but now he's having second thoughts and putting the comic on hiatus while he rethinks this whole comics-creator-career thing. He writes in the blog:
While I'm happy with what I've done creatively, the webcomics medium rewards quick, easy updates with traffic. Long, continuity-filled stories like Goats that take a long time between updates tend to stagnate, although there are certainly folks more talented than I who can pull off this difficult feat.
That's a pretty basic issue, and Rosenberg isn't the first one to run up against it. The blog growly beast has done a whole series of interviews with creators of longform webcomics (sadly, also on hiatus), and my former Digital Strips colleague Jason Sigler rounded up a bunch of links to discussions on the topic back in 2008. Some creators, like Spike (Templar, Arizona) continue to update their comics regularly, while others, like Meredith Gran (Octopus Pie) update a chapter at a time. RSS feeds make following a comic like that a no-brainer.
Rosenberg has been making his living off the strip since 2006, via the usual webcomicker methods—books, T-shirts, etc. The print edition is published by Del Rey, and the third volume is due out this month, but sales have not been as robust as Rosenberg would like. That means not enough new readers as well as not enough money.
However, he still believes in webcomics. As he told his fans,
My plan will probably involve some combination of a massive scaleback of Goats (don't worry, I'm going to try not to leave you readers hanging, there will be some sort of semi-satisfying conclusion), a new comic with (hopefully) more economic potential, and some writing for some non-comics projects I've been meaning to work on.
The whole webcomics model is still pretty new, and Rosenberg's struggle is evidence that the kinks haven't been worked out yet—and that success today does not guarantee success tomorrow. As Johanna Draper Carlson says,
I’m covering this not to wallow in someone’s pain — I feel very sorry for Rosenberg, who seems like a really nice guy with a strong sense of what he wants to accomplish — but because I think it’s an important lesson for anyone who wants to make comics. There is no job security. Even those you think of as stalwarts of the medium may be struggling. Your career is something to constantly work to improve.
And, she points out, this sort of thing happens in print comics as well (she cites a case at DC). Diversification is a good thing for creative types:
Their situation made me realize that there is very little loyalty in comics, and even doing good work won’t get you a career. You have to be thinking of the next job beyond this one.
In my fairly lengthy experience, that's true of most jobs, other than being a tenured professor.