Why do you think, every hundred years or so, we get a new pandemic? It's likely a coincidence, but that doesn't mean there isn't a reason. We live in an age where travel is so easy, people do it for fun, despite the fact we evolved to only form tribes of around 150 people. It was only a matter of time before we saw even a moderately infectious pathogen give us a widespread, novel disease. Top that with a generation of careless ne'er-do-wells and a societal structure built like a Jenga tower---all I can say is, we get what we deserve.