Why was Trump so successful? Because he started out rich

One of the main reasons that a lot of the Trumpitistas support him is because he is "such a good businessman".  A lot of these people seem to think he came out of nowhere and built this vast empire.  Now I'm not arguing he is a horrible businessman but he had started with quite a leg up.  He inherited $40 million from his father in 1974.  Now remember this is not $40 million in 2015 dollars this is in 1974 dollars which are worth a whole lot more.  Adjusting for CPI, his $40 million is worth $190 million in 2015 dollars.  He essentially started out about as rich as Mitt Romney without lifting a damn finger.  And let's not forget the power of compound interest, he has had 41 years since his inheritance to become a billionaire.  According to Bloomberg, he is worth $2.9 billion today, so he increased his real net worth by 15.3 times over those years.  Doing that math that means that he has had a 6.9% real annual return  for the last 41 years, which of course includes his probably lavish expenses.  Look, that certainly isn't bad and has made him a billionaire but when you do the math out, does that really sounds that fantastic considering he lived through the 80's and 90's booms and was a real estate giant during the biggest real estate bubble in history in one of the most booming cities in the country?