The roles that teachers and technology play will certainly change; but they are too intertwined for one to take over the other.
How? The basis of constructivism is that knowledge is built/fabricated/realized through relationships that exist in our environment.
This is quite different than the classical point of view that knowledge is a mostly a function of computation – and that is the way we build computers – in that image of our brains. That image is more left brained now because our circuits are linear, being based on logic, but that is changing. The internet is providing a huge network across the earth, and many are postulating that, eventually it will hit a point that it becomes sentient, each computer behaving like a neuron in a geographically vast neural net.
The belief that computers will replace teachers reminds me of the lofty idea of the noosphere. The noosphere is a belief that a world of transcendent intelligence separate from mankind will be born out of the intellectual evolution of mankind. The EGG (Earth Global Consciousness) project is a part of The Institute of Noetic Sciences (Princeton). It compares 200-bit random number sequences synchronously emitted from 65 host sites around the world to find structure that should not exist. http://noosphere.princeton.edu/
Technology genius Ray Kurzweil believes that computers will hit what he calls a ‘technological singularity’. This is the point at which, based upon current trajectories of computer tech, computer ‘consciousness/ intelligence’ with be indistinguishable from humans. He predicts it will happen in 2029. (so far, he’s been right about his tech predictions). Even if this comes to pass, based upon the tenet of constructivist intelligence – computers as smart as people will not be able to completely replace teachers because humans will still be a part of the human learner’s environment. Even if computers set about teaching other computers all about their world, they wouldn’t be successful in doing it well unless there was human interaction involved because humans would be too important a part in their environment!
Constructivism = we learn from all directions