Now I don't have any idea if he will be correct, or even what a machine that will pass the Turing test will be like. But if you accept the premise that technological advancement is on an exponential curve, half way in terms of progress will be much closer to 2029 than half way in time.
(Note I am not saying that technology is exponential or that it is following Moore's law or that it will be exponential forever or that 2x every 18 months is fact, its simply an extension of Kurzweil reasoning to its logical conclusion.)