ROWE isn't similar. You still have people telling everyone what to do. Only now the deadlines and expectations will be ridiculous. "I don't care how many hours it takes you this week, just get it done! We only care about results here.". The valve method would imply that middle manager would not exist.
I couldn't say. But it's implemented at the company headquarters and they are experimenting with it in the stores. They haven't gone back on their commitment to it. It's also been implemented at The Gap:
A Rails consultancy (I used to work for) in Atlanta called Highgroove also implements ROWE, going so far as to incorporate it into the way they deliver to the customer. It was a great way to work and operate as a business.
http://en.wikipedia.org/wiki/ROWE
The business measures performance instead of hours. At Valve the performance appears to be measured as 'shipped'.
I'd also guess that Gabe is practicing his own version of servant leadership:
http://en.wikipedia.org/wiki/Servant_leadership