Can you define successful? Only one single company from YC has gone public. To me, having "successful" illiquid stock is the definition of "not successful" from the employee's perspective.
That's a really good point, but I assume there have been other YC Companies that have exited (acquired, etc.)
Being acquired very frequently yields a payout for investors and executives, and a $0.00 check for rank-and-file employees (or even less if they foolishly exercised their stock before acquisition).
Two YC companies have gone public, actually - Dropbox and PagerDuty.
Thanks for the correction, but the point still stands. Two out of "over 2000 YC companies." [1]