I'm sorry to say I don't understand what your point clearly and this reply got me more confused. As in where else can they sell the account if not here? I mean the forum.
In the same way some try to sell here now and then reddit or Twitter accounts, for example, they can try to sell bitcointalk accounts on other bitcoin-related social media platforms (other forums, discord, telegram channels, whatever). Probably some even do that to try to go under the radar, I don't know. But the (bitcoin) world is bigger than just bitcointalk (although most "places" may not deserve attention, this is still a reality).