I mean, that's a hilariously depressing anecdote, but your title is demonstrably inaccurate. Just to take one prominent example, let's look at Jeff Bezos: he was born to teenage parents who struggled financially. His mom worked while she put herself through night school. Also, (and this is kinda beside my point but still,) Jeff graduated summa cum laude from Princeton.
And even if we take someone who came from money like Bill Gates, whose family was probably worth $4-5 million, it still doesn't make sense to say that he's a billionaire "because he won the birth lottery". (Again, he's also far from an idiot, but that's not the main point here.) How many other thousands of people are born into families worth a few million dollars, and how many of them become billionaires?
Also, what's your cutoff for "winning the birth lottery"? Hell, I'm a regular idiot who also won the birth lottery compared to 95% of the world, yet I'm still not a billionaire.
Yes, Musk is a moron, but statements like "billionaires are just regular idiots who won the birth lottery" are, in a large percentage of cases, factually untrue.