Clarke was widely known as the guy who popularized the idea of artificial satellites for communication long before he died, pretty much in the same way that pg is known for having popularized Bayesian spam filters (among other things of course).
Actually, I think writers in general just like to pretend that writers are more powerful than they are. Even The Making of the Atomic Bomb played up the weapon's literary precedent.
Let's just not confuse the lack of journalistic professionalism (is that an oxymoron?) with the man's accomplishments.