I'd rather fix the root cause of Amtrak inefficiency and have the organization benefit across the board than employ band-aid solutions around the edges.
Amtrak is supposed to be a real business. Structure it like one, run it like one, and everyone benefits. Outsourcing parts of the operation just allows what remains behind to continue on in their wasteful ways.
I agree. Amtrak should restructure like a real business. That is actually my point. If Amtrak were to restructure like a real business, among the many other changes, they would get out of the food and beverage business tomorrow. Real businesses concentrate on their core function (pardon the corporate-speak), and buy everything else from third parties. They do not clean their own buildings, they do not run their own cafeterias, or multiple other examples of things that a company must do but do are not the primary purpose of the organization. They let others do those things: firms who do those things as their primary function. That is how they cut down costs, management and overhead.
Food and beverage requires a management structure within Amtrak (actually, there are two running in parallel). Outsource it, and Amtrak food and beverage support is reduced to a minimal contract management function. A private contractor also has a management structure, but it is shared across multiple customers. That is one way the costs are lower.
This whole discussion is likely a moot point. I do not think there is even a slightest chance that Amtrak will move toward outsourced food and beverage service. There are just too many factions that are opposed to it, and some of those factions are not the least bit concerned with what is best for the promotion of passenger rail.