Do you and/or your investors have preferred stock/liquidation preferences? If so, that dramatically reduces the value of employees' stock and creates a misalignment of incentives, and my impression is that that misalignment has been the biggest source of horror stories of employees getting screwed.

If a $250M exit will make you rich, your investors happy, and your employees nothing, and you and your investors are the ones who get to decide whether to take that exit, your employees are right to value their equity grants at approximately $0. (That's not a knock on you specifically, of course - it's a claim about the importance of incentives.) Or maybe less than $0 - if you work at an established company with all cash comp you don't have to deal with watching your boss become a multimillionaire based on your hard work.