I notice there has been no announcement of service reductions on the Northeast Corridor. Just sayin;
1) That's not true. There's a ~20% service reduction on the NEC.
2) The NEC is about the only part of the Amtrak system in which passenger rail has a significant market share. Anderson's goal to build up <500 mi corridor service (which I would take to mean making other corridors more like the NEC and increasing the number of corridors) was probably a rational approach.
3) The only reason the national network exists is to provide pork-barrel spending in a larger number of more rural states. Our political system is such that legislators from rural states tend to call the shots, so providing service to rural areas is a political necessity for support for the more rational parts of the system. After all, adequate passenger service from rural towns could be provided much more cheaply (and to more locations) by funding a network of motor coach lines that connect to regional airports and corridor service stations.
4) Sleeping car and dining car service is provided on the long distance trains solely as a way to cross subsidize the service by increasing net revenue. Thus, the cost of providing the service needs to be a lot less than the additional revenue. (That's probably why sleeper fares are so high and OBS staffing is inadequate.)
5) I have priced trips on privately run excursion trains that claim to provide full traditional service (i.e. fresh cooked meals, fancy lounge service, attentive SCA's, etc.) The prices are far higher than even the highest bucket Amtrak sleeper fare for an equivalent trip. Let's face it, times have changed. White-glove service is going to cost you, and most of us probably can't afford it anymore.
6) With all that, Congress has previously expressed support for the full Amtrak network. Thus, while it may be appropriate right now to not spew out pointless greenhouse gas emissions by running empty trains, I suspect than as demand increases, most of the service will eventually be restored.