Authors:

It's much harder to write a script that involves two people in a single location than 20 people in 30 different locations.

"Michael Haneke Talks AMOUR, His Inspiration for the Film, His Casting Decisions, Physical and Emotional Demands of the Film and Shooting the Film in French". Interview with Sheila Roberts, collider.com. December 14, 2012.
It's much harder to write a script that involves two people in a single location than 20 people in 30 different locations.