There's something to this argument, in my view. I think that unions are torn between serving the "labor movement" for lack of a better term, and serving the narrow interests of their most senior or influential members.

I grew up in a suburb of Detroit at a time when the auto industry was contracting. What I recall was that senior assembly line workers (my neighbors) were working 60 hour weeks and pulling down overtime pay, while junior workers were getting laid off.

Naturally, unemployed people had no union representation at all, and this was a perfect opportunity for politicians to start stoking anti-union resentment amongst the working class, which persists today.

Meanwhile as I recall in one of the European countries, perhaps Germany, the unions negotiated with the government and agreed to a 4 day work week, in order to keep a larger number of workers employed. As reported in the US, this became fodder for "those lazy Europeans and their 4 day work weeks."

In the US, the car companies reacted by pulling the plug on entire factories and moving them to anti-union states.