I'd concluded that it was because unions these days sacrifice the welfare of the people they allegedly exist to represent in favour of political power within the ALP, which is not often used to benefit the grass root membership.
This change first showed up to me in SA when the state ALP and the Meat Workers' union (whatever it was called) did a deal to save SAMCOR from bankruptcy.
It involved allowing diseased animals to be transported to and processed for the pet food market at SAMCOR instead of being humanely killed and incinerated on the farms.
Benefits:
State ALP: no rise in unemployment figures.
SAMCOR: Survival.
Union: Survival in SA.
Workers: Well, they kept their jobs, but 640 of them got Brucellosis within 12 months and several were permanently incapacitated as a result.
There were also other incidents of dangerous illnesses caught from handling these diseased animals, but that was the big one.
I never did see figures for how many transport worker were also affected.