The article said that "common" shareholders walk out with nothing.

Typically, founders and early employees are issued only common stock, while investors are issued "preferred" shares. Unless the founding team invested their own capital alongside the angels and professional VCs involved in their rounds, it's not likely that they were preferred shareholders.

Preferred shareholders are first in line to get cash payouts after liquidation. Common shareholders are able to access cash only after all of the preferred shareholders have been paid.

I wrote a series on the subject I could share if you're interested.