One thing that noone is mentioning is that there is a major TGV passenger node just south of Paris called Massy TGV that trains from the south west of France stop at and that is a 20 minute bus ride to Orly.
Flights to Orly Airport from south western cities are not relevant from an economic point of view. It's just sad that a law would need to make this clearer, so why:
1) plane is too cheap, make airlines pay the true cost
2) train is too expensive, make trains leave and arrive on time
For French people, flights to and from like Orly are relevant with places like Guadeloupe and Martinique and Guyana, and some European destinations.
If you want to go travel the world, stay one more hour in the train, it will get you to CDG.