As detailed in The Box, the unions in NYC back in the day were strong enough that they managed to negotiate for no jobs lost when containerization came steamrol

As detailed in The Box, the unions in NYC back in the day were strong enough that they managed to negotiate for no jobs lost when containerization came steamrolling through. Lots of people for decades were paid to not work, and hiring freezes and attrition naturally declined the workforce from its highs of the 1960s and 1970s (containerization meant that roughly 100x tons of freight could be moved per person)