Another thing to consider - the entire plane either arrives at your destination, or doesn't, at the same time. So when it comes to flight delays, cancellations, diversions, etc. everyone is in the same boat.

Sure, the Airline will work a bit harder to make the annoyances of travel better for the first or biz-class passengers, but even then a screwed up flight will screw up your day no matter what cabin you're booked in.