There's a prequel category so I don't see why not

It mainly doesn't exist because it is hard to set it up in a way that would be both interesting to run and not arbitrary at the same time.

Going off of what DaHamster has said, the community has never been able to decide upon if the category would start from New Game, start from Secret Plans, what extras should be allowed, etc. We set up a leaderboard on a google sheet years ago which people used the first couple days, but since then there has been no activity on it and speaking from a community perspective, there seems to be little interest in an OT category at this current moment