Joel at Joel on Software wrote an article I remember reading that said starting over is more often than not a bad idea. For one thing, it's counterproductive as you spend exorbitant amounts of time building things that you've already built at some point. Another thing is that this is probably also a theory that will ultimately lead to "leaky abstraction". This new internet will inevitably run into problems because users do unexpected things. I can't remember who, but someone once said (Perelman perhaps?), that as technology becomes more secure, more technology becomes available to break it.
All that being said though, there are perhaps building new technologies. This is why scientists have been researching internet 2. Faster speeds, better securty, etc.: all good. However, we need to compromise and integrate old and new.
Beware of Programmers who carry screwdrivers. -- Leonard Brandwein