Depends on the stage from what I have seen. Most of the other founders I know, including myself, take 10-15% less salary than many of the employees. Also once funded, investors will expect founders will take a haircut for a while.
Second, many times(always?) a founder has personal savings wrapped up in the company.
Third, an employee can always just quit and find a new job. The founder is much more tightly bound to his/her company because of obligations to investors, other employees, clients, etc. To say that "the worst case scenario" for both is unemployment is true, but you're ignoring many other factors that make it far more likely for the founder to be stuck going down with the ship while employee walks away Scott free.
One trick to figure it out is to imagine founder being hit by bus: who will be hurt? Will family be hurt (besides losing the founder himself)? Employees? Clients? Investors? Anyone else?