That same flaw applies to the category of "billionaires".
You can't just take the marginal share price and multiply by the total number of shares to magically get a number that is conceptually equivalent to your normie's brokerage or 401K account: A normie can liquidate their portfolios tomorrow at the market price, but no billionaire can.
You can't just take the marginal share price and multiply by the total number of shares to magically get a number that is conceptually equivalent to your normie's brokerage or 401K account: A normie can liquidate their portfolios tomorrow at the market price, but no billionaire can.