In keeping with my recent theme of time-suck, there's another thing that writers have to find time for - marketing their work. Sure, big-timers like Stephen King or JK Rowling can get by on their talent and name, but most authors, even traditional ones like William Fortschen and Larry Correia, have to spend time on marketing because they're not household names. Sure, they have a fan base, but it's a) not large and rabid enough to sustain them on just a book coming out, and b) they still need to know what and when work will be published.
You can write the greatest stories, but if no one knows they're out there, you won't sell. Then you'll find yourself starving, living in a van down by the river and wondering why no one recognizes your talent. Small time writers, whether traditional or indie, have to visit message boards, send newsletters, shill for their blogs, and harangue booksellers to prop up their stuff. That takes time...time most would rather spend writing their next masterpiece.
Unfortunately, it's necessary. One must be out there. Sure, once you've had your viral moment and become the next James Patterson, it becomes self-sustaining, but that takes both time and a stroke of luck. So, daunting as it may be, frustrating as it may be, get out and promote yourself. If you don't, no one else will until you're uber-successful, and they only do it then because they want a piece of your action.