Let me reply to this - your ancestors can and did come to a new life. Moving from SF to Nebraska is not a new start. You still carry your credit score, loans, run-ins with the law and all the baggage with you. 18th century lifestyle was much more focused on physical work and as long as you were able to, you can find a job. Now, it is much more complex. Without a car, you are screwed in Nebraska. If you have a kid (or more), then you have to build up a brand new support system. The world has changed.
I think the real argument here is that it wasn't just some Joe Schmoe making the move. But the people we're talking about here are below Joe.
Moving may be easier in that it doesn't have a high risk of death, but much harder in actually surviving at your destination. You don't just grab a plot of land and start building your own house these days. America did that hundreds of years ago and charges for it now. How are you paying a security deposit in another state on minimum wage, let alone the travel and job seeking?
Typically charity. That's my one of my other comments suggested that the person moving should reach out to churches in their preferred destination. It may help them meet new people and start a network, including landing a low skill job they can utilize to make rent while they search for a better one.
How many jobs can you walk into in Nebraska and start working with no id. The nature of work has changed. Travel options are much more plentiful but those low skilled jobs aside from farming have been outsourced