While I don't think we should artificially protect such bottom-tier jobs, this transformation is still going to be very disruptive.
98% of US population used to be farmers for sustainability. Automation of farming freed up that workforce, today only 2% of the population directly farms. That (insanely high) percentage of displaced workforce is what allowed other other industries to spring up. Yes, jobs don't exist for those 9k workers - but the workforce being freed is exciting as it opens up entire potential markets that were simply impractical prior. There will always be growing pains - how do you retrain a cashier to be ~anything else? Same with Toll Booth workers on highways and the like, what else will those people do? But that's where the Govt should step in, ease the point edges of progress. Free market is great, but it does leave significant portions of individuals behind in the shortrun.
I think if you don't want to leave those people behind (you don't, it's societally disruptive to have a bunch of unemployed people who used to be able to kind of support themselves) government bodies need to step in and sponsor more retraining programs.
Like what? Name a single potential market that exists today, and is being held back by a lack of unskilled or semi-skilled labor.
When people moved off of the farms, it was because there were factory jobs to be had in the cities. It was possible to see where people would end up even before farming automation made most farmers unnecessary. As far as I can see, no such transition is apparent today. Unskilled workers are being made redundant with no new labor market to take them.
Some of these workers may get some training and become developers and robot mechanics, but many unskilled workers can't make that jump for whatever reason. It's not realistic to expect all of these people to become skilled workers.
If they were free to do anything else, they would've already considered not working in a minimum wage job. It's impractical to expect low skilled workers to suddenly pick up skilled work with no training and effort.
There is no need to artificially preserve such jobs, the market provides for them just fine. What threatens such jobs, at least today in California, is price controls on labor.