SCP-2212 has lacked an ending to its puzzles since it was posted in 2015. Staff had reserved the number for Anaxagoras when he wrote it, as detailed in this thread. Anax has claimed to be working on the last bit of the puzzle but so far it has not materialized in any meaningful way.
I don't think this is similar to articles like 087 or the flesh that hates because those articles lacking a final log could be argued as a narrative choice. Having a puzzle with no final solution cannot be portrayed in that way. Although the article isn't immediately obviously unfinished, the nature of its format screw mean that readers will have to invest time to discover that there is no ending to be unlocked.
This also isn't equivalent to serial stories because while each individual portion of a story series can stand alone, even if there is no final conclusion, everything in 2212 hinges on there being some sort of ending which currently does not exist. In short, other pages have enough narrative value to stand on their own, but the only reason 2212 is afloat and highly rated is because of people who thought there would be an ending released gave it the benefit of the doubt when it was posted.
That all being said, I don't think we ought to delete it. At least not summarily. Some people enjoy the journey even with the lack of a final ending and it's got enough content that we can't justifiably call it an eyesore or obvious half-effort in the way we summarily delete articles. Since staff were the ones with a special deal with Anaxagoras, we should contact him and request that he finish the article and give a date for him to do so. If he is unable to complete it by then, hopefully he might give permission for someone else to make some kind of ending.
tl;dr since staff were the ones who gave permission for this article to exist in the first place I think we should ask anax to either finish it or let someone make some ending content for it.
Whether you like it or not, history is on our side. We will bury you!