Employees are free to negotiate employment contracts with a startup so that their compensation is structured as primarily equity. If and when an acquisition/IPO

Employees are free to negotiate employment contracts with a startup so that their compensation is structured as primarily equity. If and when an acquisition/IPO happens, those employees will make a considerable sum. But most employees aren't willing to take on that risk and don't have the savings necessary to live off that kind of arrangement. Money is a very limited commodity in a startup and every dollar you're getting paid is equivalent to a dollar you're not investing in the company. Acquisitions reward investors, whether the investment is time or money.