I can’t sell equity in a private company to exchange for goods and services like I can stock that gets deposited in my brokerage account every six months.
=GOOGLEFINANCE("AMZN", "price")* (number of shares).
I can log into Fidelity and sell my shares during hours when the market is open and not at a discount.
This is incorrect. There is often significant unmet demand for private successful companies. Employees can often sell at close to what investors end up paying for it.