I had surmised as many as ten to fifteen years back that the evolving new norm in food service on trains will be food served at ones seat/compartment for upper class, and food available for purchase from a counter in lounge or table/buffet cars for the rest. In addition there may be a Restaurant/Diner Car for use by those that want to pay extra for the experience.
I had my head cut off and handed to me back then stating that while that may be what happens in the rest of the world, that will never happen in the US. I was willing to grant that with the rather minimal LD service in the US it may be feasible to eat the cost of fancier food service. Afterall, fifteen, or even twenty trains a day is not really that much to contend with. Well apparently not.
I will grant that my prognostication was based on what I saw unfold in India where prestigious luxury trains lost Restaurant Cars in the late '60s when they were substituted by Pantry Cars and at seat food service in all Sleepers and LD Chair Cars in those prestigious trains. The logic there was that Restaurant Cars were impractical for serving food to everyone in a 16-20 car train. Doing so would take two or three Restaurant/Kitchen car pairs (Indian Railways was operating AC Restaurant/Kitchen married pair of cars on the prestigious AC Express trains just prior to substitution by Pantry Car in late 1969, coincident with the introduction of the first Rajdhani Express, which never had Restaurant Car), and all that is potential capacity for additional passengers taken up by cars that provide a service that could be provided more efficiently. That made sense to almost everyone since demand of passenger capacity on trains so vastly outstrips supply in India. Again, I was willing to grant that demand is low in the US and trains are short, so Diners may survive.
Anyway, the latest in India is removal of Baggage Cars (checked baggage service was never popular in India when it was available anyway) and substituting a passenger carrying car for them. Platforms at present can hold upto 26 cars, and the preference is for stuffing as many cars carrying passengers as possible among those 26 cars. So they are down to two service cars Pantry and train staff, now with the progressive uniform removal of End on Generators and replacement of them by Head on Generation fed from the locomotive. Hopefully that won't come to pass in the US too.