A simple justification of a slightly less extreme position is easy enough: there were many sane people who did not predict the value of the internet, indicating that being sane and smart are not sufficient to predict such things.

There are plenty of quotes from people who were supposed to be experts (or at least well-educated) saything that heavier than air flight was impossible, computers would always be room-sized monstrosities of limited use, etc. I assume that this quote is pretty much the same idea (that future technology is unpredictable), but using a technology that is 1. more recent, and thus more relatable, and 2. not simply a matter of technology, but of adapted use; that is, most smart people might have guessed that the early internet could be made faster, webpages better, and the network more comprehensive. They simply didn't see the value that this would produce, and so assumed that technology would not move in that direction.