But do they have to submit a request if they tell the audience “fuck it, this is now a sub about X, we’ll remove everything that’s not about X”?
No that just isn't allowed. I'm not joking, the admins have removed entire mod teams and installed new ones because the mod teams decided to change the topic of the sub.
"Transferring ownership" of a collection of information which costs no money or labor to infinitely reproduce is the opposite of a good use case, it's inherently worthless