Amtrak offers this with "roomettes" all the way up to 4-person rooms, though whether it's an overnight or a day trip depends on your origin and destination (for example, Chicago to Dallas is an overnight). You mention that Germany had eliminated all but the profitable ones--well, the U.S. government loses money on these routes to keep them running even in spite of the high prices. I'd usually pay $800 roundtrip for CHI->DAL; meals _are_ included and you get I believe up to two carry-ons and two checked bags for free.
I will say it is definitely a lower stress option. You can show up 30 minutes before your train is leaving and there's no security lines. Depending on the station, it could be just an empty train station in a rural town or a large station interconnected with other transport services (e.g. Boston, Chicago).
The population you are traveling with is much different compared not only to airlines but also coach on the train. Generally your sleeper carmates are retired folks who don't want to deal with the hassle of TSA, running between connections, arriving three hours early, and so on. I've met some extremely nice people with amazing stories (you are seated with strangers at meals, so this is almost forced on you). If you are not in a hurry and have a few extra bucks, it's worth it at least once to experience the journey, especially across the Upper Midwest or coasts.