Midwest Express (YX) tried this (a whole plane of quasi-first-class seats for only a little more $$$ than coach on other airlines) for a decade or two and could

Midwest Express (YX) tried this (a whole plane of quasi-first-class seats for only a little more $$$ than coach on other airlines) for a decade or two and couldn't make a go of it either. It was great while it lasted, though.