As an employee, getting a small amount of common stock, none of those things apply: In practice, if things aren't going wonderfully, it's pretty easy for you to end up with worthless options, even when the founders and VCs end up alright. Even when the company is doing fine, founders rethinking how much equity they really want employees to have is not unheard of. Any calculation you make doesn't matter, as you are at the mercy of other people.
You'd see valuing employee equity very differently we all had not heard of, or been a part of, those horror stories.
Yes, a lot of early employees have ended up with worthless stock. That's the risk they took. There are also a lot who have become very rich.
http://www.businessinsider.com/how-liquidation-preferences-w...
Cash in the bank, on the other hand, is quite straightforward.
Second, if I'm starting my own company and taking venture funding, I'm going to be paying myself and my cofounders a healthy salary out of that funding, enough that we're not constantly wondering why we're not taking a well-paying industry job. If I'm not taking venture funding, I'm doing this because I enjoy it more than I enjoy salary, because I have enough personal funds to cover the venture being unprofitable. Any profit is a bonus, but not the primary motivator. If I'm working for someone else, profit is my primary motivator.