Am I the only one thinking that Amtrak is missing out on an untapped market: economy sleeping cars?

Railroads used to have "slumbercoaches" (economy rooms for one), and plenty of European railroads have sleeping compartments that are not first class. Those are cheaper than Amtrak's sleeping cars.

I hesitate to pay a price that is higher than flying first class, when I get Flexible Dining and no on-board lounge space (other than an Amfleet lounge straight out of the 1970s). But as long as I'd have my own room, without paying a fare as high as Amtrak charges, I'd take Amtrak a lot more.