The transition went much much slower than it does today most people are missing a very important point here.

We aren't just talking about automation of physical things we are also talking about automation of intelligence based tasks.

Also people often bring out the horse carriages as an example of how the people who controlled those just went on to become car drivers instead but the horses they never found new occupation.

Automation is replacing higher and higher levels of thinking and that is the problem. Its not just going to compete with you for your physical abilities but your mental ones. That's the big deal and thats where we are headed.

Driverless cars illuminates that point quite substantially.

So did those people get job training and move on to white collar jobs, or did their children? My guess is most of those farmers retired or died.