Ummmm ... yeah. Did you not get the word? Just being born into the right family can make you a billionaire. Dumbasses get billions for nothing more than having the right familial relation. What's more, in older eras dumbasses would inherit entire kingdoms and empires, essentially for no good reason apart from accident of birth.
Next to being born into it, marriage has always been the easiest way to make money.
However it's not quite that simple, because if you marry somebody without money (like this woman), while you theoretically get half the upside if they strike it rich ... the odds of that are extremely low. So it's not like she did nothing, she and her husband united their finances way back when he had nothing. It's like investing in Microsoft at the very beginning ... it's the early commitment, the early bet, that pays off.
On the other hand, if you are marrying into money and you don't have any yourself, usually that money will be locked up tight with a prenup and/or other legal protections.
That's why it's so rare for this sort of thing to happen at this level.