Similarly, taxes are applied to capital gains when stock is sold, not when it is received or bought. The employees would not be taxed just for receiving the stock/ownership, only once they sold it and made it liquid.
I'm sure they'll have to write down a lot of inventory because prices went down, but for tax purposes their valuation is still going to be very high based on earnings. That's why private companies other than startups rarely go this route.
edit: (in the US at least)
YMMV but an NQSO purchase agreement can be your friend.