They served a valuable purpose at a given point in time but that point has long since passed.
I can't agree with that assessment, JBP.
If ever effective protection for workers was needed, it's now. Since the global financial crisis (especially). The term "working poor" comes to mind. Job insecurity, seriously deteriorated working conditions, an increasingly casualized insecure workforce, people working 2, 3 jobs just to keep their heads above water ... I could go on & on.
I think workers need effective unions more than they ever did (based on my observations over my own working life, anyway). The problem is that these are huge challenges, tied to global trends & completely new creative solutions would be required to address them. And I don't see that established, "traditional" unions are up to the task. So fewer & fewer workers belong to those unions, because membership seems to make little difference to their situations.
I know this sounds rather pie in the sky & you might laugh at the notion, but I believe that eventually workers will need to organize on a global basis, to counter the impact of the multi-national corporations on their lives. Those workers who suicided as a result of horrendous work pressures in their Chinese factory needed protection the same as the unskilled, exploited (& rapidly becoming permanently unemployed) workers in the first world, whose situations continue deteriorate. I know that sounds far-fetched, but the continued exploitation of human & other resources (including severe environmental degradation which the impacts on the whole planet) by multi-nationals will urgently need to be addressed one of these days. Me, I really like the idea of strong, properly organized counter-force. And I think that counter-force might eventually become a necessity. (You can call me a dreamer if you like.