By your description of the problem it matches better the "Tragedy of the commons" (https://en.wikipedia.org/wiki/Tragedy_of_the_commons https://en.wikipedia.org

By your description of the problem it matches better the "Tragedy of the commons" (https://en.wikipedia.org/wiki/Tragedy_of_the_commons https://en.wikipedia.org/wiki/Tragedy_of_the_commons) than a self-fulfilling prophecy. A self-fulfilling prophecy would be if the belief that unions fail to help workers made them fail to help workers (which also happens).