Yes. And also, a 40 hours work week is already an arbitrary amount of time for someone to be working. It wasn't figured out based on how productive people are, or how to get the most out of a workforce. It's just the way things have always been done - a week divided into 7 days, no work on the Sabbath etc. It has a lot more to do with the Bible than maximising man's productivity.
But on a more general level, these same arguments were made when we went from an 80-hour standard work week to a 40-hour one.
Of course it was a hassle, and it did (temporarily) slow productivity growth, but in the long run those hick-ups didn't matter. The redistributive effects (from capital to labor) remained (at least until computers and the global economy).
Ah, but that's the thing: it ISN'T how things were always done, not by a long shot. It is only how things have been done for the lifetime of people currently in the work force. It is only 76 years old, having gone into effect in 1940. It had been pushed for since the 1800s (industrial revolution), but didn't gain enough support to become law until after the Great Depression.
Prior to that is was not at all uncommon for people to work 10-12+ hours days, 6 or even 7 days a week.
The 8 hour work day was picked perhaps mostly because it divides a day up into neat even categories, which readily made itself available for a slogan - 8 for sleep, 8 for work, 8 for yourself.
Slow down: I have trouble seeing this happening naturally, how would individual actors see it in there best interest to slow down?
Isn't that the primary focus of the MMM blog, and presumably most of the people who are devoted enough to the concept to participate on the MMM forum?
Once you have enough, the marginal utility of more becomes less than the effort required to achieve it.
Sure, there will always be some mentally unhealthy millionaires who still eat food a soup kitchens and don't turn on the heat in winter to keep the gas bill low, but the majority of people are capable of realizing a balance.
So it isn't a totally radical concept, the change would be qualitative, not quantitative.
One thing it is easy to forget is that there is really no such thing as "a company". There is just people. Collections of people. If every individual sees it in their own best interest to take weekends off, work no more than 8 hours a day, and have an occasional vacation, then it is in the best interests of "the company" to allow its employees (including management) to do so.
40 hours already IS a slow down compared to the 60-80 hour work week that preceded it, and people, collectively, did decide it was in their (our) best interests.
Anyone or any company that did choose to compete at a slower rate would be at a disadvantage and risk going broke.
That's a very common economic claim, but I don't think it is in any way valid. You don't compete at a "rate", you compete for customers.
Company A makes and sells 1000 widgets a day, as does Company B.
The market sustains 2000 widget consumers.
Now say Company A decides to scale back, and only produces 500.
Either B can speed up to take up the slack, or a Company C can come into existence, (or 500 people can go without widgets)
Regardless of which outcome occurs, there is no reason to assume that Company As remaining 500 customers would all of a sudden want to switch companies, leaving them with no customers. Why would those things be correlated?
There are millions of small businesses, independent boutiques, self-employed people who work part-time, and they don't fail just because others in the same industry work longer hours or produce more output.
There is this assumption that the only options are growth or failure, but there is also sustainable, right in the middle.