I disagree with you. Keeping mid-America populated is in long term interest of US. Mid-America is one of the most fertile landmass in the world. To farm this land, you need farmers and farm-hands. The farmers/farmhands need a support structure/community that is currently degrading as people move towards costs. Farmers are at the bottom of the totem pole in spouse selection and family formation. Nobody wants to move where farmers are and geographic area beyond reasonable driving distance inaccessible to farming communities. This leads to incest and inbreeding and all other ills that isolated communities experience. One solution, beyond farming automation, is to widen the geographical area accessible to farmers and their support structure. HSR can easily double or triple the distance covered currently by roads. HSR will bring distant communities in mid-America together.

People aren't moving out of the midwest because there aren't trains. They're moving out because there is no culture, limited natural recreation, etc. Trains aren't going to keep them there, and the low population density means the idea makes even less sense.

One event is rarely a driving force of change, it is always confluence of events that cause change. Lack of train is not root cause, it is a part of potential solutions to what ails the region. US would never had westward migration if population density was the driving force for movement. You want to populate an area, make it accessible and attractive.

> You want to populate an area, make it accessible and attractive.

You mean "start a gold rush".