In 2015, aside from the people with upgrades, most people in first-class don't want to be there (i.e. they're not there because they're wealthy, but because their disabilities or age make coach literally impossible) and most actual rich people fly private because even first class isn't great.
I find that the only thing that I can do on planes, these days, is take a pill, make sure I get 2 armrests (I'm 6' and 195 pounds) and nod off-- and I don't sleep very well. If we had 300 mph trains at competitive prices like Europe and Japan have, I'd rather take those.