The last thing first. He paints a picture where the human species may divide into two, with the rich and powerful forming a different species with designer babies and long lifespans, and others getting relegated to the existence of useless people.
By no means, he is alone in this apocalyptic vision of the future. This is indeed a fairly logical view of the future, once one fuses the ideas of technological progress, economic inequality and political domination of the rich together. There is this rather fatalistic view - that future will be better because the past has been and the human beings found a way to better themselves - but this is not the only possibility.
Best to watch his TED talk then with this perspective. His central argument that the human beings did better than the other species because of its ability to cooperate flexibly, in a large scale and with imagination needs to be interrogated with this future in mind. Here is the question - do we need to think about our society differently as we reach a certain tipping point in technological progress? Or, may be more succinctly, should our social imagination dictate our priorities for technological development?
So far, we have been sleepwalking through technological progress. The 20th century idea of specialist disciplines removed all social considerations from technological thinking, and secular science quickly became the handmaiden of short term commercial interests. The question is whether we would be able to change our course at the precipice, as we have done in the past.