I would be very upset if passengers had to start paying for their own meals. If Amtrak were really about to start doing that, then the recent cuts don't make any sense.
Think about it. Currently, the prices listed on the menu are irrelevant to most dining car passengers, whose meals are currently included in their sleeper fare. "Little things" like using real china, tablecloths, flowers, etc. are irrelevant to Amtrak - sleeper passengers are going to show up at the dining car at mealtimes anyway, so you might as well cut everything that's not absolutely necessary.
But if passengers are going to have to pay for their own meals, all of those formerly-irrelevant details are suddenly going to become very important. Amtrak is now going to have to persuade passengers to eat in the dining car, and all of those details - along with freshly prepared food made from fresh ingredients - are what will bring people to the dining car. Otherwise, people will just eat a microwaved pizza from the cafe for a fraction of the price, or bring their own food.
I just think that running a dining car that's attempting to lure customers in is exactly the opposite from running a dining car on minimal losses (which is what they're currently trying to do). They may, at some point, force diners to pay for their meals, but Amtrak's current behavior doesn't make it seem imminent.