I believe a combination of inertia and “throwing shit at the wall to see what sticks” may be applicable here.
If his recent ventures are anything to go by, he’s an “idea guy” that makes a convincing case of sounding smart enough to succeed. He makes big promises about revolutionizing something, and because of his persona as a successful inventor, investors and fans buy into those ideas.
With support behind him, he’s free to burn other people’s money in the hopes that one of his fantastical projects actually succeeds. And if it doesn’t, just sweep it under the rug like the Hyperloop.
Or, you know, he could always use his capital to fund others’ ideas and then take credit as though they were his original idea, like with Tesla.