My understanding is that it means going, loosely, to the opposite side of the state of the major metropolitan area in that state. Upstate NY is the northwest part, upstate MA is the west part, upstate PA is the northeast part. I’m looking around, and it seems to also 1) only be used on a few states, 2) usually is on the north half (but not always), and 3) is somewhat interchangable with “rural”.
When things go wrong? When things go right for coal and gas plants, the “boom” is a humanity-threatening event that already in its extremely early stages has been named the Holocene Extinction.