I heard an interview with him, and it wasn't very insightful. He says that everything will get smaller and faster with varying detail or on specific subjects. That's not very insightful.
But it's grating to see that he's getting so much media attention for such blatant disregard of the human condition. No consideration what a post-sentient-AI world would accomplish. No regard for what happens when people live to be 700 years old and population growth doesn't slow. His ideas are like genetically engineering society with no regard to the collateral damage it'd cause to the societal environment. I don't dislike Kurzweil for being an optimist, I dislike him for being arrogant.
Population growth is slowing. Dramatically. There's tons of evidence that as women are educated, they will have fewer children. And women are starting to get better educations all around the world. There's absolutely no doubt that population growth will slow (slash, is already slowing down) a bunch in the coming decades.
Second, I'm confused about the 700 number. Where does that come from? Does he think that in the next 30 years, we will be able to extend life so much that he can keep on living? Why does that stop at 700?! Doesn't he think that some time in the next 700 years we'd be able to find a way to live longer than 700?
Frankly, I doubt there's much difference between finding a way to live to 700 and finding a way to live until the end of time.