
Oxfam data suggests 60% of total billionaire wealth is derived from inheritance, monopoly power, or crony connections. This 60% does not those that were born in upper middle class and “rich families” (doctors/lawyers/etc), so if we’re including that the percentage is likely much higher.
Im not sure why you dont think we should use the global stat? The royal family are still billionaires under classical capitalist systems. It just depends on how you define self made, most people define it as using the tools that are available to the average person, and most americans dont generally have 200,000k to start with.