Perhaps my last post was rather flip. Let me get my head around what you are proposing.
The initial post shows a railroad station in Japan where a local cat somehow becomes a celebrity resulting in big sales of merchandise and even increases ridership on a local railroad. Interesting, but probably not easy or even possible to duplicate elsewhere.
Amtrak's larger stations, with big ridership from Amtrak, local commuter trains and/or buses just about always feature some kind of food service and other vendors.
Smaller stations with, say two to four trains a day, usually don't have such facilities, outside of vending machines.
Now, are you saying Amtrak should get into the food/souvenir business by running such facilities at stations where they don't exist?
Should Amtrak have souvenir stands at all its stations?
Should Amtrak make more of an effort to see that food/souvenir vendors are located at its smaller stations?
It doesn't seem like a lot of money would filter down to Amtrak's bottom line by either offering such services on its own or having vendors kicking back a portion of their business to Amtrak, certainly not enough to "save" Amtrak.
Having such services at a station would certainly enhance the travel experience, but you need a big enough passenger volume to justify such a service. A lot of place just don't have that kind of volume.
You mention Savannah as a place that could use such a service. There's six trains a day at Savannah, so there's probably enough people at any one time to justify a small stand. The market is pretty much confined to passengers (and friends and relatives seeming them off) waiting to board trains. People arriving pretty much just get off the train and leave as soon as possible. I believe the Savannah station is located outside of town in a relatively isolated spot, so there's probably no "casual" tourists coming in. A downtown location might attract some folks just looking around. So, it's not a bad idea to attract some kind of vendors to the station, but nobody's going to get rich on the operation of such a business.