Tom Preston-Werner is a great developer, probably world class. And he was offered a whopping 300K bonus by a company that earns $220K+ profit per employee annually (with a disproportionate amount of value created by the software engineers).
Lots of opportunity cost, gone. How do we offload this risk to the investors? Demand what you're worth. Take money off the table upfront.
Lesson to the Hacker News readers; you're not going to get rich by being an employee. Start your own company if you want any sort of chance of becoming rich. Otherwise forget the extra hours, live a balanced life, play with your kids, love your /(boy|girl)friend/ or spouse.