Yes the vast majority of the non-urban population is going to become urban for economic reasons. That’s been going on since the dawn of civilization (it's literally where the name “civilization” comes from), and it's not going to reversed any time soon.

So the solution is train 50 million people and tell them to move to large cities? Will the government pay for the move, or no? What about the skyrocketing rents in the large cities with the large influx? What about their homes and land they own now? Write it off? What exactly would you train them to do?

That's got a lot of red flags in the details. Ignoring that, it doesn't sound anywhere near ideal solution. I would expect something better. I think getting the federal government into building things again instead of contracting it out would be a start, similar to FDR's works programs. I'm sure it will get a lot of resistance, but the same way we've been doing things isn't working.

> So the solution is train 50 million people and tell them to move to large cities?

No, that's not a solution or what they need to be told to do, the move is just what is largely going to happen over time.

Insofar as there as a policy solution, it's supporting the effected population through the transition, which, certainly includes funding retraining those who can benefit from that, assisting relocation, and assisting those who can't benefit from retraining.

(While it's politically unlikely in the near term, UBI could address much of that with less friction and overhead than targeted programs.)

> I would expect something better. I think getting the federal government into building things again instead of contracting it out would be a start, similar to FDR's works programs.

Whether it's government jobs or contractor jobs makes no difference; FDRs works programs weren't significant because of that but instead because of the scale of the work. But those were to deal with a major business cycle downturn, not an effort to hold back the long-term rural→urban transition.

Unless your works program is a permanent one building monuments to waste in rural areas, it’s beside the point of the problem you are trying to address

Surely most of them have jobs? Even then, the top 5 cities could each handle a million more people - admitably it would require more infrastructure.

Also there is no rule that big problems can't have simple solutions.

Many of them are on some sort of government assistance with part time or low paying jobs. Also it would be 10 million over 5 cities. That has big problems in and of itself.

>Also there is no rule that big problems can't have simple solutions.

No, but if the solution was simple, it would have been solved already.