There's probably an essay to be written on the disappearance of the intercity bus network over the past 35 years. There's very little of Greyhound (which I think now also includes Trailways), and very few independent carriers. The map predates the emergence of the internet-tickets-only, subscription bus services that tempt advocates of transportation policies without scheduled and surely without regulated or subsidized common carriers. But Destination: Freedom suggests these are sparse in Ohio anyway.
The Amtrak map, however, doesn't provide sufficient context. In 1979, most of the passenger service in Ohio was a single train either way in the middle of the night: the Lake Shore between Chicago and New York or Boston, with a connecting Detroit - Toledo bus; the Broadway Limited between Chicago and New York or Washington (dividing at Harrisburg or Philadelphia: the Capitol Limited first came back as a Washington - Pittsburgh connecting train); the National Limited between Kansas City and New York or Washington (also dividing at Harrisburg or Philadelphia and seriously overworked west of St. Louis as a day train across central Missouri connecting with the Southwest Limited); the Shenandoah on an overnight Washington - Cumberland - Cincinnati schedule, and the Cardinal, at that time a daily Washington - Charlottesville - Cincinnati - Chicago schedule (at the time, running via Peru, Indiana). The Cardinal and the National crossed tracks at Richmond, Indiana, long a hub of The Pennsylvania Railroad, but with no semblance of connectivity.
The sparse passenger network in Ohio is, as Destination: Freedom notes, a consequence of Amtrak preserving passenger trains that were running as of April 30, 1971.
Ohio lies between the Northeast and Chicago, and overnight trains between them go through Ohio in the middle of the night. In the past, there were more trains that offered a broader choice of departure times, so there were trains that stopped in Ohio during the day. There were also shorter-distance trains between cities in Ohio, but they did not last into the Amtrak era, which began in 1971.Regular readers will recall that we emphasized Penn Central's success in getting rid of passenger trains west of Buffalo or Pittsburgh here. In 1971, there was little interest in returning passenger trains to freight-only routes.