Things change. Technologies evolve and merge, cultures assimilate, new cultures arise, and our civilization accretes knowledge, methods, habits, etc.
Fifteen years ago, few people had heard of the now ubiquitous Internet. Now the majority of our population knows about google, youtube, wikis, blogs, email, etc.
A few years back, I read Kurzweil's "The Age of Spiritual Machines" and recently my daughter read "As the Future Catches You" by Juan Enriquez (required summer reading for her new high school) which she discussed with him ("Daddy! This guy says the same things you keep saying!")
We forget today that there were visionaries 30 and 50 years ago who foresaw part of what we have today. The vision was blurry, but it was true. (Playing a multiplayer game over the net 25 years ago, I could easily imagine a day when we would play with hundreds of players, but I never dreamed of the current MMOGs...though some did, as in "Snow Crash".)
Jules Verne wrote "From the Earth to the Moon" a century before we actually did it. His vision was also very blurry, writing from either farther back in time, but it was a true vision.
Where are we headed 10 or 20 years out? 30? 50?