I’m a firm believer that it isn’t going to be aliens who stomp humanity. It’s going to be something we created.
Because when Skynet becomes self aware or when we get sucked into the Matrix, someone’s going to ask the computers how do we fix the planet? The answer’s going to be, “Get rid of the humans.”
And when it comes to protecting the planet, humans keep showing they have the morality of Peter Lorre’s character in “M”.