I think Elon Musk is a prime example of why this guy is probably wrong. Elon Musk needed quite some time and money to organise sending a rocket successfully into space. He hired a lot of people for their expertise, because he didn't know everything and didn't have the time to learn everything by himself, let alone build it.
If an Elon Musk were to attack this problem in the way such a problem needs to be attacked, then things would be interesting. Humans are more complex than rockets.