Ever since the winner of the inaugural season, Kelly Clarkson, went on to make a very successful career for herself, the winners of the competition have largely fallen flat on their faces as soon as the competition ended. Sure, there have been a few successes, like Carrie Underwood in the country scene. But for the most part, we never hear from these people again.
Why is that? In theory, American Idol showcases the best and brightest talents in the country. They are whittled down week by week until, finally, we have the best (according to popular vote anyway...) singer in the competition. So what's the problem?
The answer lies in the question: American Idol produces singers. Increasingly, however, it seems that vocal talent is not what Americans look for in their music choices. A quick check of the steady success of Britney Spears should attest to that fact. Artists nowadays are forgoing actual vocal talent in favor of Auto-Tune, sensual dance moves, and over the top production value. And Americans can't get enough of it. (I'm not saying that there are no talented popular artists; for example Adele certainly has loads of talent, and despite her antics, Lady Gaga is actually a very gifted vocalist.)
So maybe it's counterintuitive to hold singing competitions anymore... we should probably be voting on who can don the most outrageous costume and gyrate like a spinning top.