Yes, but their definition of self-made to include people who "got a head start from wealthy parents and moneyed background," like Rupert Murdoch. I think most people would consider the next level on their scale, "came from a middle- or upper-middle-class background" (e.g. Mark Zuckerberg) to be a more appropriate cut-off.

Not for nothing, but the Forbes 400 list that year included Elizabeth Holmes because of her 50% stake in Theranos, valued at $9 billion; last year it was valued at $800 million. This is not the only example of wealth being more made-up than self-made.