Oh I don't know, how they abandon almost half of the stuff they start making? Pupperidge Farm sends its regards.
Or how they have constant infighting, causing writers to leave the project one after the other? Hugs, Will and other departed writers send their regards.
Sure, a few pieces of content might have plans for additions, but that doesn't mean they are outright abandoned. It goes right back to the fact not everybody will always be happy with everything that is being written at any given point in time. They have limited pool resources and have to pick and choose what they think they can get done in a timely manner and still please people and themselves. If they are focusing on side characters then they aren't focusing on dungeons or the main story. If they're focusing on the main story they aren't focusing on dungeons or side characters...
Just so we're clear, Hugs broke the companion rules and then tried to say that the devs were biased against people with mental illness when he was held to the rules. He disappeared from the community multiple times before CoC2, for good reason I might add, and Savin decided to give him a chance with a companion despite this because Hugs seemed to be in a better place. He then preceded to disappear again, which was against the companion guidelines, and when he came back was angry that Savin wouldn't let him pick right back up with Berwyn. It escalated and Savin outright banned him from writing. And that's not to mention some of the longstanding community writers providing anecdotes on Hugs behavior when it came to collaborations.
Will was suffering from depression and writer's block. I'm not totally aware of if one caused the other, but his productivity at the very least took a massive drop (only writing a few one-off scenes a year) and according to Nonesuch, the one large product he finished was not of sufficient quality. The same project that Fen publicly offered to work with him on at a later date. I can't verify the veracity of whether his departure was entirely voluntary, but considering this went on for over a year with Will still being paid the whole time, I don't think it's outside the realm of reason for Will to depart of his own volition. Could they have done more? Maybe, but at the end of the day getting help needed to be Will's choice.
Most of the other writers left for health reasons, like Night Trap or Mistybirb. Misty is honestly probably the closest to infighting, but even that is a stretch since she wasn't staff. JimThermic got a SFW writing job and didn't want one to interfere with the other. Most just plain disappear for no apparent reason like SoAndSo. Hell, some just randomly pop back up like Couch. Or go to jail for tax evasion.