Frankly, there are already plenty of museum-quality baggage cars in museums.
* Half the Amtrak Heritage baggage cars are converted coaches. They're completely shot since the suspension wasn't designed for baggage service, and they have had all interior details stripped. Nobody wants them. Best case, they'll be stripped fort parts. More likely they'll be melted for metal value.
* The other half have mostly *also* had all their original interior details stripped over the decades. They're also mostly bad choices for preservation or restoration, though a few might survive.
* Conversion to any use other than museum service would require putting in windows (restoring them in some cases, I guess). This makes it absurdly involved, expensive, and undesirable compared to taking a decaying coach, sleeper, cafe, diner, or observation car.
The Heritage dining cars are much, much more attractive for anyone interested in preservation, restoration, private car service, or even entertainment. Seemingly the tourist train and charter private-car markets can never get enough dining cars -- and they're *also* popular as seating attractions at railroad museums and even just at theme restaurants. I would expect much, much more interest in those -- they should all fetch prices better than scrap.