I guess from Amtrak's standpoint, if they get you there, all is well. But from the passenger's standpoint, unless they just want "transportation" (in that case, flying would often be the logical choice, both in time and $$) from point A to B, it does matter. Amtrak is well aware that many passengers on the CZ, as well as some other LD trains, are there solely for experiencing the scenery from the trains. Their schedules even reflect that. So, imo, that doesn't let them off the hook. I think they should inform passengers and do all they can to help with alternate arrangements. If I'm paying for train, I expect train, and if that can't be delivered, they should go all out to remedy it.
Any other mode of transportation would be expected to do that. Change ship to plane? Change plane to train? (That one would be wonderful with most of us here at AU, but not for most flyers.) I don't think any of that would go over well with their passengers! Changing train to bus doesn't go over well with some of Amtrak's passengers, either.
Bottom line: We need to ask? (and hope we get one of the "good" agents)