Getting lucky (Paypal) and being a good grifter (Tesla) does not equal having brains. At most, if one wanted to be generous, you could say SpaceX was a venture made at an opportune time, but I would attribute that less to brains than luck, since the driving impetus for its founding was not "NASA is phasing out certain services which private companies will need to pick up" but "I just got rich and now I want to fund space exploration." Which, to be fair, is better than what most people do when they first get rich - but is hardly proof of intelligence.