I'm in two minds about catering on trains.
Firstly I think, as others have mentioned, it's like a downward spiral... Buffet cars not making money = reducing down menu = trolley = less desirable food = less revenue and so on. Then you have other issues, i.e. unreliability of services being available etc. I absolutely agree what others say regarding overall customer experience. It's like how if a clothes shop in a particular location is making a loss, and the company may be choosing to keep it open to allow customers who ordered products online to collect. The same reason for passengers using particular services or operators for the facilities.
It just feels like they need to be a bit smarter with the whole perception of "on board food", especially with the trolleys. Change it up a bit! Introduce deals, i.e. Coffee and a muffin/chocolate for a competitive price. Maybe do some more market research and find out what people actually want to eat on board from a trolley. I.e. hot bacon rolls in the morning (Obviously you'd need something to at least keep them warm) but things like that could be very profitable. I don't see much point in wheeling around some uninspired trolley full of Kitkats and Quavers. If on board railway food comes back in a big way, it would need an extensive marketing campaign to change perceptions, and then the service afterwards would need to be consistent to maintain an image. Also, focusing on services that are usually busier. I.e. even if it's a stopping service, like if are families going to the beach etc. Another alternative could be to run a reduced catering service but with better options. I.e. Staff boards at station X with a basket of pasties or sandwiches with crisps and drinks and then leaves at station Y and then being on the next service to X. In that way you'd catch the passengers doing long distance journeys but save company costs.
The reality is that most catering seems half-arsed at the moment.
Glad to see that FGW's pullman is reportedly doing well. With their travelling chef services probably going soon, the lack of marketing and availability probably didn't help. I'm not familiar with the pricing however.
I do hope the new IEP trains will have some form of shop or catering, especially between cities like Bristol and London or Cardiff and London!