I think it's such an interesting aspect of Future that we see that the Gem shards aren't dead. Legitimately. This isn't me goofing off or criticizing the epilogue for "un-killing" the CGs in the core of the Earth.
Frankly, I think that this is way more fucked up.
A Gem needs all their pieces to be, well, themselves. We see this clearly here. And from Peridot's description, we know that a gem shard is just a small, confused part of a person, desperately trying to find its missing pieces.
It requires every single piece to make that Gem whole. She's 99% complete, yet inert, without that last little piece.
Imagine, if you will, a giant mass of flesh. Just a heaping mound of stitched together organs and pieces of skin. Some of it is faces. Some of it is lungs. Some of it is still beating hearts.
Worse yet, they're constantly yearning for their original bodies. Together, they can move one arm- only for a short time, only until they get tired, but hey, at least it's a buff arm, right?
Wouldn't you want it to be dead? Wouldn't the concept of it being sentient be horrifying? That this scientific mockery of life has every single memory of being an individual person in every single cell it has, but it's so unstable and broken that all it can think of is "I need to be whole".
Thankfully, the Cluster gets along with itself. It binds with itself. But it's still just pieces of a person, struggling and pulsating and full of anguish.
