Hi John,
As with everything on the internet, this article and action that's making waves around the internet is an oversimplification on what is a really complex problem with a lot of factors and variables.
Your example with a factory worker is great example for that specific type of work, an assembly line, but much like the mentality of "lets work 6 hours instead of 8" craze that's going on it would only apply and benefit a specific type of employee - the average uninterested employee. This is guy/gal is a programmer, accountant, secretary, QA tester whatever that is good enough at what he does to get by and even promote very slowly, has mild interest in what he does for work but not enough to call it passion and does the work mostly for the money. That is actually the majority of intellectual employees, that need a job to live but can't find the dream role that's perfect for them to pump them full of life and excitement every day.
You see Sir, you are privileged enough to have a passion and set of skills that you've worked to develop over the years that actually enable you to go out and do whatever it is that you do best and have fun with it, while still bringing you quite enough money to live off. You wouldn't be able to say that about the guitarists, painters, artists, etc out there who are in very low demand and extremely high supply. Yes the elite of these people will do well, but only the elite. You are an elite in your field John, a well known and recognised symbol of the IT and Gaming industry. Most people are not and cannot afford to live off their dreams.
Thus while this new 6 hour system would not apply to you, because you are passionate about what you do and can invest non-stop effort in what you're doing (don't get me wrong, I'm the same just not as good or popular, Yet :D, but I am fortunate enough to live off of what I like doing best) for everyone else, this system would bring benefit for average employees that are willing to keep their Facebook time for home and work while at work. They will have a few more hours for themselves, their kids, their wives, and potentially even allow them the two extra hours a day they need to transform their hobbies into actual financial successes. \
In my opinion, the solution to this whole conundrum is to stop treating all businesses as they are assembly lines and analyse them on a case by case basis. For example in a micro games studio where you only have 10 valuable employees, a task based system might be a much better approach. "We need the sprites done by date x, the core mechanics by date y, and the sound by date z. I don't care if you work 9 to 5, 6 to 24 or 20 minutes a day, as long as they are complete in time we're golden. Then we can have meetings with the whole team to analyse the quality of your work and based on everyone's input we can determine a set of bonuses for different traits of your work (quality, speed, efficiency, reusability, etc).". This is of course an off the top of my head idea but it would work well in a very small studio where everyone has their meetings at the local Pub.
Unfortunately doing such an analysis and discovery on a large business would be extremely costly, so what's the next best thing? Follow the already well established trend, and copy whatever solution works for a different company (and copy it poorly without understanding why it works for that company). There is a reason why google employees in the US live on the Google campus, but nobody bothers to find out why thus what we get is silly generalisations like the 6 hour work day.
Blimey I went on quite a ramble didn't I? Oh well... apologies for the wall of text for all those that'll end up reading it.
And do have a lovely day! :)