What about the large spectrum of contributions between "passive, deserving of dismissal" and "top-3 contributor"? This seems a little too black and white.
Ideally, people are vesting on a share of stock proportional to their contribution. That's all I mean. If people are "passive" compared to what they are expected to do, they shouldn't be there any more.
Some investors are passive, giving money and doing little else. They don't vest and their roll is clear.
My comment is a bit black and white, but was commenting in the context of the thread: employees getting stock and expected to contribute proportionally.