I think speech techniques and speech therapy general is more of a band-aid solution which helps some more than others, its unfortunate its the only treatment for stuttering. For me my speech therapy techniques lost effectiveness as soon as I had to use them in a real world scenario, basically any medium to high stress situation. I think fluency also tends to fluctuate during different times of your life and that may also be the issue with your speech techniques failing. My stammering was crippling in my mid early to mid twenties where I was practically mute and no speech technique would have worked. Now in my late twenties my fluency has improved drastically...out of the blue, and suddenly speech techniques and overall fluency are easier.