People are very predictable too. On the whole they walk on the surface of the Earth and don't deviate from it more than a few km.
It's a very misleading assumption to say people don't deviate far from where they live. I know here in Canada it's not only common, but considered abnormal if people don't regularly go to cottage country, frequently travelling a minimum of 100km to get there.
Just because city-dwellers naively believe the city has everything they need, doesn't mean the 4/5ths of the population that permanently live outside of large cities behave like those in the cities.
Even when I lived in the UK, it was rare to know people who didn't travel far frequently.
Reread what you're responding to; he's talking about people staying within that distance of the surface of the earth, not people staying within that distance of their home city. The list of people who have been more than ~25 km away from the surface of the earth is very, very small.
It was a good answer to the previous post: staying within 25 km of the earth's surface (with a few exceptions) means we're all "predictable" in some sense, but we're all very unpredictable in other senses -- much like the pendulum is predictable in some ways and not in others.