"Rowling has lived a "rags to riches" life story, in which she progressed from living on state benefits to being the world's first billionaire author."
https://en.wikipedia.org/wiki/J._K._Rowling
Oprah's another:
https://en.wikipedia.org/wiki/J._K._Rowling
Oprah's another:
Oprah followed the more usual path of "get a job, get promoted, rinse repeat" until she was a household name before she started her own company. Per the article you yourself linked, she was co-anchoring the local evening news at 19. That isn't the same thing as taking a risk on a start-up.
Oprah bootstrapped herself out of poverty to become a media billionaire. You might say she took the long way by routing through various jobs to get the money, but she still came from poverty, founded companies, and became a billionaire.