Code golf challenges have no defined endpoint.
In the early days of CGCC, we would often write challenges with a defined time limit in mind; e.g. "This is code-golf, so the shortest answer after one week wins". Now, time limits have largely been relegated to tags where they're necessary (some challenges tagged king-of-the-hill, cops-and-robbers, etc.), with the idea that a challenge should be valuable to future golfers. Indeed, as new languages and golfing strategies have been developed, old challenges have been revived with many answers that couldn't have existed years ago.
Some have argued that even accepting answers discourages people from participating. Announcing the winner in the question itself is a step too far. And if you were thinking of continuously updating the leaderboard for all eternity, it's much better to include the Stack Snippet leaderboard in your question. Or, people can just use this userscript.
What's the "accepted answer"?
Are questions in which no answer is the best allowed?