Isn’t that the justification France used when they went to 37 hours and aren’t they down to 35 now? Fewer hours means a couple more positions to keep an eye on things, even if productivity doesn’t drop for everyone else.
In France this didn't really work, in corporate jobs anyways, people would just work their old hours anyway, which they then take off as 'vacation days' - typically in the vacation periods where there's downtime anyways. Doesn't seem like it's worked to help increase total employment.
Interacting with companies in several countries, my impression is that many companies in France will hire more people and share knowledge so that the higher-than-average 'vacations days' do not impact business continuity. It's certainly the case in companies that I've worked for.
I haven't seen any studies but I'd not be surprised if this translates into an increase in total employment.
Another benefit I perceive is that by assuming that people will be absent, companies have higher bus factors by default and the increased resilience that goes with it. And of course, the reduced efficiency that comes hand in hand. I've lived through enough crises to favour resilience.
The protection racket so many of my fellow American programmers euphemistically refer to as job security, - or just unselfconsciously don’t refer to or think about at all - has always left me cold. Occasionally it rises to the level of disgust.
One of the important currencies in our industry is trust, and people only trust That Guy grudgingly. Sharing info is often reciprocated, and you have a clearer picture of the whole project. Something very necessary if you ever hope to be in leadership.