Q. It seems to me that more and more people are attending writers' conferences or submitting material, so why aren't more people published?
A. If you asked editors for an answer to this question, they would likely be able to give you a definitive answer as to why they don't publish more of the submissions that come across their desk or through their computer. They would tell you it was because so little of what they see meets their needs and ultimately the needs or interests of their readers. The majority of the submissions come from would-be writers who know nothing about the publisher or publication, haven't looked at the publisher's website, haven't closely studied the writers' guidelines, haven't seen one or more sample copies of the publication or read any books from the particular book publisher.
Another possibility is that some would-be writers let their ego get in the way and think they know more about how the publishing industry should work—as opposed to how it actually works. Writers need to learn what is expected of them and fulfill that as well as possible. Complaining that they should have been treated differently will get them nowhere.
Probably the most prevalent reason so many writers never see their byline in print is because they lack the persistence and follow through—or the courage—to actually submit their manuscripts. Writing takes more persistence than almost any other vocation, because the feedback and motivation—as well as the payoff—come so long after the work is completed. And often—when it does come—it's at a level much lower than they expected.
The reality is that most writers who do finally make it, make it because sharing their message or God-given talent is more important that the fame or the money.