I love the bit about Kellogs 6-hour workday. I think this is something that should be stressed more. That and not work and more work but work done more efficiently. What is the point in paying somebody to work 8 hours if they get done with there days work in say, 6 hours? A 9-5 or otherwise long workday is a complete trap, and I feel it only serves to demoralize and to make people complacent. People aren't made to work those kind of hours and conditions, and become essentially a slave to their work. Wake up, go to work, go home, cook dinner, sleep, repeat. A 6 hour workday really would (and seems to have been proven) to make a great difference. I for one would take less pay to work 6 hours a day and have more time to pursue various activities. But when you have a 40 hour work week it's likely easier to fall prey to consumerism and try to buy your happiness. This would be due to having less time to truly pursue different and more wholesome activities, or not having the energy or desire to at the end of a longer workday. I could see that being a major reason that the industry lobbied for the 40 hour workweek. To stray from the article, I also believe that it's unnecessary to travel to work many jobs, especially in Engineering and Computer Sciences. Many people that I know that are in IT/Software Engineering/Computer Science actually work from home once a week or once every couple of weeks, due to being fully capable of doing the same exact work outside of the office. I also know of a few Engineering Consulting firms that don't even have an office. Every person is out of a different location, works from home, and they have meetings via software similar to Skype or Google Hangouts. A lot of the time you don't need to be in an office or on-site location to do Engineering if you're dealing with the design, analysis, or other paperwork. The only necessity would be having a central server where information can be accessed, saved, and reviewed. I truly hope that 15-20 years down the line more people start to realize all of the above, or at least that I can find a company that agrees with some of these views.
The thing is, a lot of businesses are moving away from the 8 hour work day, but unless it is done properly, it can make things a whole lot worse. France, for example, used to be the envy of most of Europe with their 35-hour week and 5 compulsory weeks of vacation. Of late, however, a lot of companies have stopped imposing fixed working hours on their employees. You come in when you have something to do, and leave when you don't. Good news, right? Except now, there's no way to limit the amount of work the company makes you do. Unless you're in a job based on shifts (waiting on tables, hairdressing, cashiering), you actually end up working well over 40 hours a week, simply because you have insanely short deadlines and more and more projects piled on you all the time. If you take your foot off the gas for just a bit, and miss a couple of deadlines, it can be grounds for being laid off, or for not getting a pay rise. In some places, you just have to put in long hours, except now you don't even get overtime. It's an absolute mess. The problem is that a time-based work week is more or less obsolete in most professions now. It was made for the industrial age, when workers were expected to just turn up at a factory, do their thing and then go home and have nothing to do with work for the rest of the 16 hours. Nowadays, if you work in the service industry, you're taking work home, constantly scrambling to get in your projects on time. Things aren't necessarily better.
It seems small team companies might really benefit from this flexibility, and large task-based employment (cashier, factory, etc.) might do well with a shorter work day, but as you mention, it's the professional service jobs with a large number of employees that can't manage as well with either. You can't really ask a professor or a lawyer to shorten their work week in a meaningful way. Also, there isn't anything to keep their competition from working to the extent that they can bear.