So by extension his control of it - and the ability to shut it down or simply say "If you back Donald Trump, you're off Twitter" - is a bargaining position.
Obviously Trump - master of the deal - knows this.
There are weaknesses in the GOP that are waiting to be exploited. Now they've advertised themselves for sale to the highest bidder, why wouldn't that be Musk ?
I'm going with the suggestion that this all kicked off because Musks recommendation for the NASA job was rejected by Trump. Space is Musks dream, and it may have been unwise for Trump to think it was just another deal.