I can't speak for anybody else. But I have been on both sides of the fence. I had speech therapy through the public schools in my youth. Not at all helpful. I saw an SLP in my teens for a couple years. Barely helped at all. I went back to that same SLP in my twenties. I went from having a severe stutter to being very fluent. Severe meaning never a fluent sentence. In under a year I was fluent. The x Factor for me was me. When I went back to the SLP in my 20s, I went all in. I did the work everyday. I didn't take it seriously in my teens. I didn't believe I could become fluent. I went to therapy but I didn't do the work during the week. I was very fortunate to have access to a great SLP. Finding a competent speech therapist is one of the challenges.