The speaker argues that there is no reason to expect successive sigmoid curves to sustain an exponential trend indefinitely.

“get further up the overall exponential trend um sure yes he does say that but as i say in the book there is absolutely no reason why that is something that's always going to happen and indeed his own sort of generalization of moore's law when he puts that together it ignores much of the early history of computing where stuff like that did not happen if you go back to you”