Kurzweill is 65, so he has 20-25 years to live probably in the currently system; figures he would say 20-25 years. The blog owner probably thinks he has 40-50 years more to live so is gunning for 40 years. I remember Larry Ellison mentioning 20 years for such a revolution in a speech some years ago. People are less likely to say 'in 100 years' if they won't make that themselves. 1000 years is easier to talk about than 'just' after you're dead yourself, but what would be the fun in saying 'in 1000 years' ; no-one would listen.