Agreed that Gorbachev's statement is not "proof" as such - it is weak evidence, but all that is available. Case study evidence is also evidence, even if weak.
There's a difference between poltiical writing and independent case studies.
Even if Gorbachev did honestly believe the techniques worked, he might have gotten political power because he believed them to be good in an enviroment where most people considered them ineffective. He also doesn't had a good opportunity to compare.
We at Intentional Insights would appreciate your help with feedback on optimize a workbook that conveys rational thinking to find meaning and purpose in life for a broad audience. Last time, we asked for your feedback, and we changed our content offerings based on comments we received from fellow Less Wrongers, as you can see from the Edit to this post. We would be glad to update our beliefs again and revise the workbook based on your feedback.
For a bit of context, the workbook is part of our efforts to promote rational thinking to a broad audience and thus raise the sanity waterline. It’s based on research on how other societies besides the United States helped their citizens find meaning and purpose, such as research I did on the Soviet Union and Zuckerman did on Sweden and Denmark. It’s also based on research on the contemporary United States by psychologists such as Steger, Duffy and Dik, Seligman, and others.
The target audience is reason-minded youth and young adults, especially secular-oriented ones. The goal is to get such people to engage with academic research on how our minds work, and thus get them interested in exploring rational thinking more broadly, eventually getting them turned on to more advanced rationality, such as found on Less Wrong itself. The workbook is written in a style aimed to create cognitive ease, with narratives, personal stories, graphics, and research-based exercises.
Here is the link to the workbook draft itself. Any and all suggestions are welcomed, and thanks for taking the time to engage with this workbook and give your feedback – much appreciated!