What I was trying to get at is that the value of money is both absolutely consistent (unit of account) but also completely situational ($10 can save a life). At the same time, the IRR of investing on public markets, like an index fund tracking the S&P 500, is exactly the same for everyone, and anyone can invest 10% of their net worth, whether that is $1,000 or $10,000,000.

The original comment was that holding money generates nothing, you have to risk it, and I completely agree. You can risk 20% of your net worth and you're not risking your livelihood, and odds are in ~8 years your investment will have doubled, and your net worth increased by 20%. For some people that's a thousand dollars, others it's ten million. If you want to double your net worth in less than 30 years, you're going to have to risk a lot more. Everyone has access to the same returns on the public market (and we restrict access to private markets for very good reasons).

So it's a literal definition of risk, and as a percentage of net worth it works well. The problem of massive wealth inequality to me is completely adjacent to risking capital in return for investment returns.