Your part of the country may be different, but the major cities (typically rail hubs) in mine have fairly dense towns at regular intervals along the tracks leading out of the city.

Unfortunately, for the past century the larger cities have been steadily sucking their population and talent away. Hub and spoke rail systems are an excellent way to revitalize these towns and encourage population balancing.

Because not everyone wants to live in a Singaporean econobox.

Traditionally, the limitation on this has been weakness / corruption of local government vs the major freight railroads.

Amtrak, with proper Congressional support, could play an interesting part in reopening existing rail to passenger traffic.