The reason I chose Elon Musk is because he's a household name and most people are familiar with his story. However, 67% of all "high-net-worth" Americans are self made, with only 8% directly inheriting their wealth. [1] If you consider only men (as women have an easier time marrying into wealth) it's 76%.

I used to be more aligned with what you're saying. An eye opening paper for me was this [2]. I ran into that when actually searching information on the chiseling out of the middle class. And that paper does describe that. In 1979 the middle class controlled 46% of all income, and the upper/rich classes controlled 30%. Today (well at least today as of 2014) the rich and upper class control 63% with the middle class left with 26%. There's even been a chiseling out of the middle class as a whole declining from 38.8% of society to 32% of society.

But the eye opener is this. This is the change in the size of each economic group between 1979 and 2014:

- Rich: 0.1% -> 1.8%

- Upper Middle Class: 12.9% -> 29.4%

- Middle Class: 38.8% -> 32%

- Lower Middle Class: 23.9% -> 17.1%

- Poor or Near-Poor: 24.3% -> 19.8%

If you're concerned that partisan bias may be tilting those numbers (as such figures are certainly subject to a variety of different interpretations), wiki has a section on the political stance of the Urban Institute [3]. Beyond that, that paper is quite readable and their methodology very transparent. It's extremely eye opening.

[1] - https://www.fa-mag.com/news/most-millionaires-self-made--stu...

[2] - https://www.urban.org/research/publication/growing-size-and-...

[3] - https://en.wikipedia.org/wiki/Urban_Institute#Political_stan...