There's also the unstated implication that "anyone can do it if they work hard for it" - basically saying it used to be you had to be born into a wealthy family to be one of the richest people in the world and now you can be the richest person in the world based on merit alone (thus rich people are inherently meritorious).
Somehow all of those explanations seem to gloss over the fact that you generally need to be born into a wealthy family in order to have the cushion to take the risks that allow you to collect billions. As an example, Paul Graham would have been far less likely to attend Cornell and Harvard if his father had a blue collar factory job instead of being a nuclear physicist. Almost none of the 'bootstrap billionaires' of the tech world come from less than an upper middle-class background, but like PG they are quite fond of suggesting that their success was entirely due to 'merit'.
