Yes, The Witness was defeated at the end of The Final Shape, essentially tackling the primary antagonist of the entire Destiny story up to that point, the architect of not just humanity's downfall but countless other civilizations. This concluded the Light and Darkness Saga, what they refer to as the story from D1's launch through the end of TFS. You can make arguments about whether The Witness was properly set up or a good villain or whatever, point is that that's the story they ended up telling, and it reached its conclusion.
But that doesn't mean that there can't be other antagonists, which is what they've been trying to build up with the current storyline, the Fate Saga. In this, the antagonists are some (possibly all) of the Nine, a group of extradimensional dark matter beings tied to the planets of the Solar System and the Sun. Despite being vast and ancient and powerful, they are also exceptionally fragile and tied down by the gravity wells that they were born from, an existence they do not enjoy. Due to their dark matter nature, they have difficulty directly interacting with the material world, but being outside our dimension also gives them a unique view of time and the ability to manipulate events to suit their ends. They also view paracausality (Light and Darkness) as a means to potentially free themselves from their chains and become something more.
So in The Edge of Fate, we learn that the Nine have been manipulating events for a long time, causing the deaths of people that will eventually become Guardians or ripping someone useful to them through time to where they need them to be. Then there's the reveal at the end where another minor antagonist attempted to forcibly pull one of the Nine, III (Earth), into our reality to compel it to her service, but the process ended up killing it, and its death will lead to the eventual death of Earth. It managed to send a message to the player, though, that they needed to "bind the Nine," which the current theory on is binding their consciousness to something in the physical world to limit their powers somehow. This was followed up in Renegades where VI (Saturn) gave one of its followers information on energy referred to as "Eclipse," which essentially works as an anti-paracausality beam that flat-out kills Guardians and Ghosts alike. Its goal was to use the deaths of countless Guardians to fuel its ascendancy through the Hive's Sword Logic and use that as a shortcut to freeing itself from its current existence.
And that's where we're at now. There are really a couple of major issues, the first being that the Nine aren't exceptionally compelling as antagonists. The last time we heard anything from them was all the way back in 2020, and even that was minor, so to say they've had very little bearing on the story for quite some time is an understatement. They've been very scarcely mentioned and little time has been spent on character development, so they just kind of came out of nowhere. Furthermore, they're so alien that they're difficult to relate to or understand. They're higher-dimensional beings with inscrutable motives and personalities who don't see time as we do, and the only visual reference we have for one is a gigantic space jellyfish corpse. That's a lot to ask for the average player to engage with.
And the other big issue, naturally, is that the story has been on hold for way too long. Say what you will about the old seasonal model and the inability to actually play through those campaigns anymore, at least it kept the story beats coming at a reasonable cadence for those playing along at the time. Every couple of months, you'd have some more story to chew on, building up to the next thing. Meanwhile, we've effectively only had two campaigns this year, with a very minor side story in between, and it's been five months now since the last campaign, so we're overdue even for another minor campaign. They started to build up a new storyline that we're all supposed to get invested in for the next few years, and then they immediately hit the brakes. How is anyone supposed to stay invested when there's nothing to experience?
(I'm not even going to get into the Winnower, that's a whole other can of worms.)
) which is Cabals (local orcs but in suits) homeworld. It was destroyed by the Hive (local undead) and more precisely their the Goddess of War which had a lot build up the year before and generally Hive's lore is most interesting part of the lore. There is also a Cabal's leader who is our ally and she helped guardians a lot so we can help her.
