Indeed, transporting people to the center is not what causes problems in the Paris area. That's the way the transportation system was set up a hundred years ago. And the advantages of centralised office space are many : prestige of the address, attraction of the workplace to workers, easiness of commercial and organisational networking - most people spend most of their working time interacting with people rather than in front of a screen, actually.

And I believe the wealthier portion of the work force is getting the nicer offices, in Paris or La Défence, whereas those with lower wages and prestige get relegated to those faceless "office concentrations" which are not connected to public transportation. And thus the public transportation in the suburbs problem is not only about efficiency and environment, but also social equality : the lower wage workers have to spend more money and time commuting.

Un roi sans divertissement est un homme plein de misères