"The message here is that if you want to work at a company where people are doing big and important things, you have to give up everything. It’s okay to say that."

No, it isn't.

Yahoo! is certainly not doing 'big and important' things. They are a search engine that can't figure out how to get it's rapidly decreasing market share from rapidly decreasing. And the CEO wants everyone in the company to give up everything - happiness, work life balance, a life outside of search engine work -for that cause.

Unless Yahoo! decides they don't need you all of sudden - you know, if headcount is too high or they decide your department isn't part of the 'goal'. Then they can cut you loose, despite the fact that you gave up everything for them.

So, translation: Yahoo! and other companies want you to give up everything for them, but they will give up nothing.

Deeper translation: Yahoo! is doomed.