Does Trump not question what is Musk is actually doing with his day or is he not on the payroll? I suppose they have so much information on one another they are just a friendship of convenience.
I think Trump is happy to have both the money that Musk lobs at him and the backing of twitter and Musk is happy to have the ear of the President and the lucrative contracts that will come his way from Federal Govt for Space X
But, their fractious personalities and massive egos suggest that this will be another Bromance, like the one with Farage that could go tits up in an instant.

