An autopilot can’t be controlled from the ground. And it’s not a ‘miracle’ that the aircraft didn’t hit a city or town, since the vast majority of land in the U.S. is uninhabited. It would have really, really bad luck for the aircraft to come down over a populated area.
There was a case a few years ago of a guy who tried to prop-start his Piper Cub without tying it down properly first, and it took off without him, flew a long way, and crash landed into a tree with very little damage. He shipped it home, fixed it up, and is flying it again.
There have been a number of cases of pilots falling asleep at the controls and running out of gas. One I read about a few years ago, the guy woke up when the engine quit from fuel starvation, but he happened to be within gliding range of an airport and he glided it in and landed. I imagine it must have been pretty embarassing, but it’s better than being dead.