"It worked for dock workers when containers were invented." There's a long description of that in "The Box", by Marc Levinson. It sort of worked for workers. But, in some major cases, the entire port moved. In San Francisco, the Port of San Francisco essentially shut down as a freight operation and the container traffic went to a new container port in Oakland. In London, the container traffic went to a new non-union port on the east coast, and the huge London dock complex was abandoned. (Now it's housing and the finance industry.)
The Longshoreman's Union in San Francisco negotiated a "guaranteed annual income" deal, but only for two years ending in 1977.[1] They still have a good pay rate for full "class A" longshoremen: $36.68 plus various bonuses and shift differentials. It's possible to make $150K a year as a longshoreman. And you probably don't have to do heavy lifting. But there aren't that many of them left.
Consumers would otherwise have had to pay some other amount for their unemployment, poverty, and reliance on handouts.
Laying all of them off also has costs, both financial and human.
If every human being was replaced by a robot, the cost savings to consumers would be enormous. There would also not be any consumers, as nobody would have money to spend.
The Longshoreman's Union in San Francisco negotiated a "guaranteed annual income" deal, but only for two years ending in 1977.[1] They still have a good pay rate for full "class A" longshoremen: $36.68 plus various bonuses and shift differentials. It's possible to make $150K a year as a longshoreman. And you probably don't have to do heavy lifting. But there aren't that many of them left.
[1] http://archive.ilwu.org/wp-content/uploads/2015/04/19750207....