No, by idle I meant idle, not what's left over after you've already put in a day's work.
I reckon if one is willing to sacrifice those two today, they could have much idle time. I knew at least one chronically homeless person for whom I think this is a barrier to getting back to a normal life. Idle time is addictive. I don't think he became homeless decades ago to gain more idle time, but he did get accustomed to it.
I think this gets to the heart of it. The people hanging out in the cages in the article were not the average person. They were almost invariably well-to-do people who didn't need to work for a living. Free time and some security from harm against potential failures (or wastes of time) are two ingredients for innovation. The majority of our technological innovators come from priveleged backgrounds, for that reason (in addition to money granting them access to the right education, networks and technology).