Okay, so after seeing Gem Drill, I have to admit I did really love the way that Steven ultimately ended up ending the situation passively. It’s what he’s always done, and having the Cluster ultimately broken up and reduced once again to shards feels kinda out of character for how empathetic Steven usually is. But while this was a satisfying and very emotional conclusion to the Cluster arc, I don’t really think this was the end for the Cluster per say.

Steven Universe as a show has never really left anything forgotten about. Malachite was a very serious threat, even when it was still trapped underneath the Ocean all the way back at the end of Season 1. So I have a pretty strong feeling that we won’t forget about the Cluster anytime soon, or at the very least it’s going to serve some other purpose than ripping the planet apart.

Now that Malachite’s been dealt with, Jasper’s missing, and Lapis is presumably no longer posing an antagonist role against the Crystal Gems (like she did in Ocean Gem), and the Cluster is bubbled, the next big threat is most likely Yellow Diamond. Who I imagine is rather upset that her gigantic Geo Weapon was never fully brought to fruition. And with Peridot now on the run from Homeworld, I’m guessing Yellow Diamond’s going to break earth apart herself, piece by piece. And she won’t be coming with just one ship. Given her importance, odds are she’ll bring an armada of ships on par (if not better) than Peridot’s. And the gems couldn’t do a thing against that. So, if Yellow Diamond does come to Earth, bringing the greatest and latest Gem tech that Homeworld has to offer, the Crystal Gems are pretty much screwed at this point.

But then there’s still the Cluster.

Now, the Cluster’s been germinating in the Earth for thousands of years now, and it’s been safely trapped within a bubble, permanently keeping it in stasis where it can do no harm, and that’s exactly where we want it to be. But what can you do with a bubble?

You can Teleport it.

Generally to the Gem Temple, but I’m assuming this technique predates the creation of the Crystal Gem Temple, so presumably you can send these things anywhere, possibly even outside of Earth’s orbit, where the bubble can be safely popped, and the Cluster can emerge in a manner that isn’t dangerous to the Earth. We know it’ll take time for Yellow Diamond to arrive on Earth via long distance space travel, roughly the time it took Peridot (if not faster.) But during that time, the Cluster’s going to communicate. Billions upon billions of shards learning, speaking, and expressing themselves to one another. And it’s been noted multiple times by Garnet, as well as others, that communication is an important factor of a healthy fusion, much like a relationship. And the cluster right now is essentially the largest poly relationship on the planet. Should the time come where the Crystal Gems need to ask the Cluster for help, and ultimately pop the bubble; it may even emerge as a healthy fusion, with a unified consciousness, better and healthier than anything Yellow Diamond could’ve hot glued together, and all because of Steven.

TL;DR: The Gems are now in a position where the Cluster could be their ally rather than a threat to the Earth, and I believe that the Cluster will ultimately help fend off Yellow Diamond’s forces, when the time comes.