Forbes actually has a way of tracking this. Its called the self made score. Essentially a 1 is someone who inherited money and did not grow their wealth and a 10 is someone who came from poverty. Anyone above a five is someone who started a business and did not inherit the business. A six is someone who either invested in a business or was an employee of the business.
Kim is a seven on the self made score. She is self made but she got a massive advantage because of her wealthy parents and family connections.
To give a comparison to put the score into perspective. Trump has a 4 on the self made score, Bill Gates is an 8 and Oprah Winfrey is a 10.