I have been living in the US for the last 7 years now. I frequently fly to India via Europe most of the time. I traveled a lot in India & US on domestic flights too. And most of the time I arrive at the airport an hour before my flight either international or domestic. I have never missed my flight even once.

The only time I missed my flight was when I arrived at Heathrow 45 minutes before my flight to Ireland and I was told that I missed the flight. They were done loading the luggage and closed the luggage gate or something.

This whole thing that you should arrive 3 hours before an International flight and 2 hours before a domestic flight in my opinion was started by the Airlines/Airports in my opinion. They want you to arrive at the airport very early because:

1. You get hungry and spend money on the over-expensive airport food or you get bored and spend money in the airport shops.
2. These airlines overbook flights, so if everyone arrives early this would give them ample time to think about what they need to do if they don't have enough seats on the airplane for everyone. It's great for the Airline, but a waste of your time.
   

Am I wrong or is my thesis valid?