WARNING: This article contains major spoilers for Action Comics #1000, which is available now.
Tom King and Clay Mann's Superman story in Action Comics #1000 offers a beautiful and touching farewell to Ma and Pa Kent, and that honestly... kind of stinks. The adoptive parents of the Man of Steel proved to be an important part of Clark Kent's formative years, but now they're dead, and despite Rebirth rewriting so many aspects of DC's comic book continuity, it doesn't look like they're coming back. Especially not after a send off this good.
The Death and Life and Death of Ma and Pa Kent
The Kents have proven to be such an essential part of Superman, it's impossible to tell his story without including their's. An alien baby is rocketed to Earth just as his home planet is destroyed, and a doting couple from the heartlands of America, with no children of their own, take him in. Jonathan and Martha Kent instill a young Clark with the strong moral compass he needs to become Superman, and be the most famous superhero of them all.
They play a role in just about every major adaption of the Man of Steel to date. We see them take him in during Richard Donner's Superman, raise him in TV's Superboy, mold him in Man of Steel. They even played prominent roles in Lois and Clark: The New Adventures of Superman and Smallville. Even Superman: The Animated Series features Ma and Pa Kent playing a part in Superman's life.
The sad truth of the matter is, for most of the character's 80 years of history, the Kents have actually been dead. As elderly parents, they passed away before they could see their son grow up to become the man -- and hero -- he would be. It wasn't until the DC Universe was rebooted following the events of Crisis on Infinite Earths, during John Byrne's run on Man of Steel, that the Kents were brought back to the land of the living.
Subsequent adaptations looked to this version of Superman to craft compelling versions of Clark Kent's home life. They were the loving parents back home in Kansas, the dispensers of wisdom for a younger Man of Steel, and the only family he had to hold onto. It's a shame that the New 52 wiped them from the land of the living and deposited them back into the graves they inhabited for so long. There's no potential in that, especially now that Jon Kent is around.