No, he won't want to buy Bitcointalk, never.
Because bitcointalk is not a fancy platform to build connections and shill your posts to walls, notifications of other users who are in or not in your connection/ friend/ follower list.
It is different than social media platforms like Facebook or Twitter when your notifications will be spammed with many statuses and tweets from others.
Bitcointalk is not a place for Elon Musk to play with his jokes that he always loves to do.
There's even a higher tendency for him to pay someone to build his own community platform because he has the money and popularity to do so, than to settle in this forum. Also, I think elon musk is targeting non-crypto users more because the things he would state will easily drive them crazy of following his 'calls' unlikely of crypto-inclined people who'd criticize some of his decisions on which is which, in terms of investment. I doubt as well that the owner of this forum would sell this easily, especially if he/she is earning enough from multiple projects being released weekly or more frequent. Also, if we would somehow 'read' his mind, he'd go directly for things which will generate bigger profit or power perhaps, to save him time.