Certainly our technological growth over time has not been linear.  It is more like a exponential curve.  Kevin Kelly has a very fascinating lecture on technology in which he applies the theory of evolution to technological growth.  I would recommend it to get an interesting perspective on it:  http://www.ted.com/index.php/talks/view/id/19.


 Artificial intelligence, I believe has a theory about a singularity being reached in technological growth.  After we invent tools, we use these new tools to create even more efficient tools.  We then use these new efficient tools to create even better tools fast than we could with our old tools.  So you can see, once a new technology is created it facilitates the creation of other technologies.


Not to mention 60-70 years ago digital chips and computers were relatively new and barely advancing.  Once started their growth can now only be described using an exponential curve.