The Midwest, as an example, has roughly the same size and population as France with a larger economy. In fact, if you overlay the French TGV network onto the Midwest with Chicago where Paris is, you get a pretty good approximation of where major Midwestern cities are located: https://www.reddit.com/r/MapPorn/s/NMr3J3gt8C
Frankly, these don’t look like locations that that many people want to travel between.
The French urban areas on the TGV aren’t very big; Montpelier, for example, has a total of 600,000 people in its metro area, which is roughly the same size as Toledo, OH or Wichita, KS.
And yeah, there would be a fair amount of demand just to Chicago the same way there is a fair amount of demand to Paris, in that they’re both the regional powerhouses with finance, HQs, etc.