If security is something the employees are worried about, they should not have joined a start-up for whom an exit is their best chance.

Startups are volatile environments with risky financial conditions, hopefully driven by people for whom making the best impact in their chosen area is the most important thing. It should all be about the product, making the best decision for the product, championing the product.

Employees are valuable and necessary. I would never argue that employees contribute less then management in general. However, it's not a founder's place to make sure they get security via an exit... It's their place to make their product fantastic, which as a side-effect, should keep the employees employed.

If they want security, they should bet on a stable job in a stable market. It's boring, it's not as challenging... But it's safe.