I'd be very interested to see just how much the savings is. After all there is the added expense of having to buy a new plate for every meal, and I understand that the amount of garbage has almost trippled. And Amtrak has to pay to have all that trash picked up and thrown away.
And then of course not having that second person in the kitchen hurts customer service, slows down overall service, and because of that means that less people actually get to eat in the dining car. Less people eating means less revenue. I for one can't imagine that the savings realized by cutting the second person is very much, if any, in the face of all that.