Okay, you asked for it, even though your point is obviously well-reasoned: According to this
CNBC report, only half of the passengers who travel First Class on Delta have paid for their tickets (rather than received upgrades as loyal customers) and this is supposedly already a industry-leading proportion. As the primary motivation to offer First Class seems to be keeping your best customers loyal rather than actually making money, such accommodation types are much easier to justify for a publicly listed carrier than a government-subsidized railroad (note that you can only redeem Preference points for travel on Prestige Class outside the peak season, i.e. when there is no opportunity cost in offering the upgrade). Therefore, it doesn't seem as a coincidence that
Italo is among the only railroads I'm aware of which offer premium (i.e. above Business) accommodations (even though Amtrak does the trick of simply branding the Economy Class on its
Acela Express as "Business Class", so that they can offer a "First Class" with only two accommodation classes). Other than Italo, I only know of
Railjet and JR East with their superb
Gran Class...