Great article, Jenn. It made me think.
While I agree with your points in general, I think introducing limitations that suit you and your style, and focusing your writing efforts on what you really want to develop could make even a public 30-day writing challenge useful. And possibly fun too, both for you and your readers.
For example, you may decide on running such a challenge with a daily word limit. Wait, make it a character limit! Why not start a twitter account exclusively for this purpose, and write a flash fiction piece no longer than a single tweet each and every day? Focus on the story. Or write snappy mood pieces that you could use in your lengthier short stories later on. Build a repository — your own collection of stock paragraphs. Like photos, only transmuted into words.
This is just an idea, and just a single example, of course. I’m not sure it would work for everyone. But it might. A pre-planned path (self-imposed limitations) and a good flashlight (a carefully chosen focus) may help finding a way through the woods when it’s dark. And it might even be fun to follow for others. :)
Thank you again for the inspiring article.