This is a great idea - but I would have been more impressed if it was one of Brad's team writing this piece - and not him.
Three years ago my partners and I at Foundry Group decided to experiment with a month off the grid. Each of us goes away for a month and the other three (now four) cover for him. It’s been remarkably successful for us, both individually and as a partnership.
Why? Because 'at the top' things like this are very easy to do. If you are a coder in an engineering company in one of Brad's investments - I wonder what the reaction would be if they asked for similar benefits.
It is not clear from this article whether this is the only 'vacation' that Brad takes - but I am pretty sure it isn't - based on other posts in his blog.