This might be a dumb question, but: Who would benefit from killing the Internet? I can understand a short term hostage situation where the attackers would ask for a fee to free a site, but even then how would they send their ransom request? By snail mail?
I can imagine a situation where the editors would tell a "news flash" like this:"We just got news that yesterday a ransom letter dated a week ago had arrived..." Just like a hundred years ago.