First of all, we're on the same page about the risk profile of working for larger companies being better for employees. But the reality is there aren't enough of those jobs for every single startup employee out there to get one. Some people also like the startup environment - move fast and break things, etc.
Your denominator (5000) is _all_ investments that YC has made. You need to look at investments of a certain vintage, e.g., 10 years or more. You also need to include all the other companies of that vintage where employees did well (way more companies in that cohort have sold or gone public). The result is 0.06% is a gross understimation of the success rate (where success is defined as successful enough for early employees to make a lot of money).
Your denominator (5000) is _all_ investments that YC has made. You need to look at investments of a certain vintage, e.g., 10 years or more. You also need to include all the other companies of that vintage where employees did well (way more companies in that cohort have sold or gone public). The result is 0.06% is a gross understimation of the success rate (where success is defined as successful enough for early employees to make a lot of money).