The really important dreams are rarely good investments. I don't think anyone seriously believes the manned exploration of Mars will turn any profit. A true believer wouldn't care. There are people who would hand over a dozen winning lotto tickets for a chance to go to Mars. Musk faces that decision every day. That makes it difficult for me to believe tales of his madman/dreamer rhetoric.
And I'm not criticizing musk the person. I'm say that here is a disconnect between the public dreamer persona and the known actions of the physical person.