Elon Musk is no idiot. He knows how to create a huge and profitable company. He didn't become a billionaire by accident -- it was by design and planning.
Perhaps we should consider that above statement in each of our lives... Mine included.
Planning alone won't guarantee success. Planning with 'wiggle room' will. I don't think he invisioned all this from the very beginning -- he sees opportunities and figures out ways to implement those opportunities into his current businesses.