Diners cost too much to run. The European trains no longer use them either. They just have a 'bistro' car that serves sandwiches, drinks and snacks. It can be manned by a single person.
Not true about European diners. There are fewer than there used to be but still quite a few, and their number is actually increasing in some places.
Hope just seems to spring eternal on here. Diners are disappearing everywhere and especially in Europe as more and more routes become high speed. Even the overnights are disappearing and they don't carry diners nor do any of.the regionals.
I think you can't really compare the USA to Europe in this respect.
In Europe the diners are disappearing because the trains they are on are disappearing.
1) All the emphasis on high speed trains has taken focus away from long distance services and management consider them something that's causing a lot of bother for little return.
2) Politicians stand up for high speed trains because they are sexy and modern and offer nice photo-ops. Nobody stands up for long distance trains any more.
3) The transition from a train of cars pulled by a locomotive, where you merely changed the locomotive when you reached the border between two countries, to fixed and dedicated formations is making it more and more difficult to operate long distance trains. Back in the 1970s and 1980s, the cars used on LD trains were of a standardized configuration laid down jointly by the European railroads. Any car could thus basically go anywhere and staff knew how to use them, even when they were off the home system, as the principle elemenets and controls were in the same places, seats numbered in the same pattern etc A new service could and often was started up at short notice. Today the trains are pretty much optimized for one particular route or service. For example when the iron curtian fell, the railroads were very quick in implementing LD trains connecting city pairs that hadn't seen direct trains in decades. With today's fixed formations that would be impossible.
4) Because long distance trains sometimes overlap with high speed corridors, management is concerned about market cannibalization and this is killing off or truncating long distance trains.For example RENFE has killed off all the Elipsos night trains just because there is a very partial overlap with the Barcelona to paris high-speed route. If you want to go by train from somewhere like Zurich to somewhere like Alicante, it actually takes about 5 hours longer today than it did prior to high-speed trains. That's progress.
5) The railroads are claiming they don't like night trains because they like to close down lines at night to do maintenance and repairs. This is becoming more of an issue now that operations and infrastructure are vested in separate legal entities and the infrastructure companies thus have more muscle to push trains out. Freight trains also mostly run at night in Europe and the same problem is blighting growth in freight, but at least freight companies have more financial muscle which improves their negotiating situation. Because of the unpredicatbility of maintenance, many LD trains are removing intermediate stops in smaller places to provide more flexibility in routeing. But it is precisely the smaller places that provide a vital reason for the existence of these trains. So the downward spiral continues.
So the problem in Europe is the long-distance trains are disappearing. In some years time, there will only be high-speed system for journeys up to four or five hours, there will be commuter and regional systems in the areas that support them, and practically nothing else. Longer distance passengers will have to go to the airlines or face highly complex choices with multiple changes of trains. there is thus no longer a niche for on-train sit-down dining.
I don't know if the US is heading in a similar direction. maybe once the high-speed system start build up momentum the LD trains will be forgotten here too. But I think we're still some way from there, and a lot may still happen so I wouldn't assume the worst right now.