The union movement has been the best middle class job creating program that America has ever had, and it doesn't cost the government a dime.
Manufacturing and other unskilled professions that were union jobs, that allowed people to live a middle-class life, are disappearing both because unions are disappearing and because of the global nature of the economy.
I would say the issue for the labor movement in the United States is not structural... there is no correlation between the success of workers and how the labor movement is structured.
I would say that workers in general, and white workers particularly, are correct that their economic wellbeing is deteriorating.
It has no enforceable standards to stop a union from conspiring with employers to keep another stronger union out or from negotiating contracts with lower pay and standards that members of another union have spent a lifetime establishing.
The question is always 'What is the role of a labor movement?' How much is about collective bargaining, how much is about social change for all workers?