South Shore Line was the original user of this station, and they still own it despite South Shore Line trains having been rerouted to the airport since 1992. The move of the station to the South Bend Airport was so anticipated to stimulate train travel to the airport that the whole facility had its name changed to Michiana Regional Transportation Center --- the only airport I knew of that did not have the word "airport" in its name. That name was short-lived, and they went back to having South Bend in the facility's name, as well as what it really is, an airport.
The writer has a point. How many passengers does the South Shore Line really feed to the airport? It is not good for travel from South Bend itself to the airport, and it does not work for travel between what is now solely the South Bend Amtrak station and the airport, although with a wye type connection this could be possible.
If NICTD were to double track the easternmost portion of the line allowing more service between Michigan City and South Bend, perhaps both the current airport terminus as well as the one adjacent to Amtrak could be used by alternating trains. Or with push-pull equipment and the wye connection I suggested above, both termini could be served.