Not that it's much of a downside for us; if you live in the west you are competing with people who don't do much outside of 9-5. We have the benefit of having the ability to apply the Chinese "work till you're dead" mindset and gaining a competitive advantage, on an individual scale.
It all comes at great human cost of course, but it's not like it's not an effective method.
The weird thing is that if you work at a company where this isn't the norm, then people will ask you to "slow down" or "take it easy". I believed them, until I realized that was their tactic to make sure you don't "steal" credit from them by working harder.
On the other hand, if you work at a company where "work always" is the mentality, then it's much harder to do that "one simple trick" where you get more work done by working more.
Definitely true from a office politics standpoint. And incredibly painful. Not all problems are solvable in the office and this is for sure one of them - when I was in this position, the only thing I could do was switch jobs.