Most people know exactly the value of their time and the opportunity cost is in things like food and shelter. Wealthy people don't work for a living so their time isn't obviously valuable at all, have their wealth tied up in stocks and so can't predict their returns, and aren't materially affected by gaining or losing even billions of dollars.

Most people don't fly private because they can't afford it. Duh.

(And when we're dealing with real people, not homo economicus, it's clear that working 100 hours a week and hiring staff to do everything else would be miserable even if it made financial sense.)

EDIT: Replaced "poor people" with "most people".