Did the economic prosperity of the 1920s bring positive social and cultural changes to US society?

Not when you consider the financial and industrial decrease of 1929 and subsequent years, which led to the Great Depression. Even though there were widespread social reforms in the early 20s, the economic depression that was to come by 1929 made it impossible for people to work toward "common good" goals. The Great Depression was the Great Interrupter of many people's lives, including those who took their lives when they lost all of their wealth... and for the families they left behind. In a morbid sense, the Great Depression made "social good" an every person's practice, because everyone had to help each other to just survive.