I.e., the early employees do a great job. The business has a value of $100M and their non-liquid shares are worth $0.5M. The business raises $100M with a 1x liquidation preference. The startup fails, and eventually sells for $50M. Instead of getting $0.1M-$0.25M, those early employees get nothing.
Further, never forget that employees are plebes, and your and my shares are subject to a 6 month lockup that, for example, founders aren't necessarily subject to. See Mark Pincus dumping 16.5m shares of stock for $11.64 ($190m) two months before, and for $3.18 more, than regular employees could [1]. Zuckerberg also sold 6% of fb at ipo, though since the price didn't cater investors don't seem to object. Founders often can also take cash off the table. Note that I don't necessarily think that's bad, but as in the cases of Secret and Digg, employees don't walk away from failed companies with millions.
edit: actually, Pincus appears to have sold at twice the price available to employees ($12 vs $6.09), not $11.64 vs $8.46.
On April 3, 2012, the secondary offering closed at a price of $12.00. Mark
Pincus, Zynga’s founder and a director, netted approximately $192 million in
proceeds; the other three selling Zynga directors sold several million
dollars each in the secondary offering. Zynga’s stock declined significantly
following the secondary offering to a closing price of $6.09 on the date
that the original lockup restrictions ended, and a closing price of $5.36
and $3.00 per share, respectively, on the two extended lockup periods
applicable to the selling Zynga directors. [2]
[1] http://www.law360.com/articles/596929/zynga-founder-can-t-sl...[2] http://www.law360.com/articles/608007/a-closer-look-at-delaw...
Did Kevin Rose sell shares in Digg?
It is ruined by a simple fact that this hypothetical startup earned just 50 cents for every dollar raised -- I don't think anyone should expect a nice payout here.