Perhaps the question that really needs asking is not whether Kurzweil is correct in his future projections but do we really want to allow technology to change our lives, relationships and civilizations so completely. More importantly, why do we wholeheartedly welcome such extensive changes?
We have evolved over millenia to be a species that must work together, build connections with others, if we are to survive as a species. Yet the technology Kurzweil so welcomes is the antithesis of connection. He may talk about how we will all be connected through technology yet it is only the illusion of connection. We learn as a species through shared experiences. We learn as individuals through empathy, much of which is gained through shared events. I understand your hurt because I have felt pain.
Virtual reality is NOT reality. In fact it is the offer of fake connection for the real connections of real people and events.
Moreover, why should we want to embrace a reality for which we are not biologically or psychologically suited? Our brains are wonderfully evolved to process and manage information, and perhaps most importantly if you follow the work of certain neuroscientists (i.e., Damasio) emotional input. Where does emotion live in this new world of Kurzweil's?
Lastly, are we to expect that everyone will have access to this nanobot-enhanced world? What about the poor? What about the middle-class? I suspect that Kurzweil's brave new medical and technical breakthroughs would only be available to those who could afford them. Just like medical care in America today, many people would simply be cut out and left behind.
The upshot of technology such as this at the beck and call of the wealthy is that they (who are already often extremely out of touch with the real world of everyday people) would become even more out of touch. What does this say for the decisions that they will make that influence us all? I suspect those decisions will do even less to draw us together. Why should the wealthy and powerful make decisions that help everyday people? Through virtual reality they can become even more insulated from the results of their acts. Those left on the outside (probably the mass of humanity) are not as "human" or advanced are we? So, like the 21st century version of Puritanism with this form of technology as God, everyone without it will be found wanting and cast off into the technological and civil underworld.
Note, I am not a Luddite. I would not question all new technology but something as fundamentally important as how humans interact with the world and others is something to be closely considered and examined before letting it loose to do untold damage.
So I ask again -- Why do we so easily welcome this technology without closely examining potential results from every angle?