It may be pure jealousy on Trump’s part that Musk is far richer than he is.
The problem with Trump in some of these things is this makes him look very petty and I would rather have Musk as an Ally, not an enemy or a rival. If Musk was a natural Born Citizen maybe he would run for President, but he can’t.
That didn’t stop Obama, Cruz, Jindal, Rubio or Harris.