Most people will agree almost nothing that's complex gets deployed on schedule. And here, he's discussing the entire unfolding of the future of technology, a very complex process. This reminds me of William Gibson's quote, "The future is already here – it's just not evenly distributed". So, although it may be possible to create certain technologies in the future, economics will determine their adoption rate.
But, overall I agree with Kurzweil. The world will be a very different place in 20 years. And, it will probably be a bumpy ride. Medicine will change more in the next 20 years than in all previous years. In 10 years, robots will be everywhere, doing a significant portion of the labor that's done today by humans. In 10 years(2024), most new cars sold will have the capability to drive themselves. the list goes on and on.
The problem with such predictions is that we perceive things moving linearly, even when they aren't. Kurzweil is aware of that, but that awareness doesn't make his predictions more accurate.
Try this game: It's 1960, you are given a vision of the future, and what you see is now, with smart phones in every third hand and a cell phone in every pocket. Your problem is that you don't know what year you're seeing. So given what 1960 was like, how many years until now?
And try to be honest. Keep in mind that in 1960, most men still wore hats!
Or we could regress a very, very long way back if we don’t get control of the criminally insane who are running the governments of the world. In ten or twenty years we could be remembering movies like “The Road Warrior” and wishing things had turned out that well.