I know what the tipping point means. It's the "nighness" you mentioned that I see nowhere in sight. The only reason I dwell is because of it's potential to be more harm than good. Giving people a false sense that they're "on the right track" might make them FEEL good, but that makes them complacent. Then they'll never be motivated to actually solve problems and GET ON THE RIGHT TRACK.
"whether the idea reaches a very small group of key people can trigger a dramatic epidemic of change in society."
Who are these "key" people? Again, where is the evidence? Otherwise, it's just talk. And potentially damaging talk to boot.