Where HSR excels is in being able to service several city pairs on a single line. The Northeast Corridor is a great example: you can have a single train service all pairs of {Washington, Baltimore, Philadelphia, NYC, Boston} at negligible extra expense in time and money. Thus you can add in stops like Providence, which don't generate all that many trips on their own, simply because it is literally on the way to where you're going.

The problem with the US Midwest is that there's a lot of these third-tier cities, but you have to go out of your way to connect them. Who wants to go between Columbus and Indianapolis--the highway between the two cities is pretty empty. Even worse, the few collinear city triples you can come up with all completely miss the primary destination of the entire region, Chicago. If you want to go from Chicago to Columbus, Indianapolis, and especially Dayton, are not on your way.