When humans went to a six day work week, the wealthy said it would end civilization.
When we went to a five day work week, they said the same.
Same as when we said overtime needs more pay, women should be paid more, 9 year olds can’t work in coal mines, and basically every other labor law from the past 10,000 years.
And we are more productive than ever due to automation. I bet 2 days would be enough to keep society running. Nothing fancy though. 3 would be enough for economic growth.