Before I start, I've only had 3 hours sleep. Apologies if this sounds aggressive. Ok. To flip what you've said, anybody who stutters that sits back and does nothing to help themselves will make zero progress. Any effort is better than no effort. It's discouraging to say some won't be guaranteed fluency. I believe everybody can! Though it may takes some people more work than others. This view of mine comes from experience of feeling victimised (wondering "Why do I stutter, why me?!) and doing nothing to get out of this rut. Since then I've been more proactive. Done a lot of experimenting on myself with regards to the effectiveness of different practices. The options/advice for progress should be there for people. Contrary to popular belief, I feel fluency should be the goal. Some, or a lot of, PWS have negative feelings towards their speech because of their lack of fluency. Managing/controlling your stutter is definitely a goal to achieve. That's part of the climb when it comes to achieving fluency. But that's for another time. As you can tell I'm playing devil's advocate. I'm asking the questions and sharing the beliefs that hardly anybody else does. So please take this with a pinch of salt and see if as food for thought.