we moved our startup from London to SV in Jan 2007 partly due to this line of thinking. it is false, no-one productively works 24/7 and trying to do so is a mistake i don’t intend to repeat on my next startup.

the vision of the workaholic, always at their desk entrepreneur is in my experience usually propagated by people with little actual operational experience of raw startups. this post from Naval Ravikant sums up what i've learnt about productivity, http://startupboy.com/2005/11/29/the-80-hour-myth/

and on the london vs SV work ethic. my peers in london work just as hard as my peers in SV.