To be fair, for those jobs the 5 day workweek, as it is known traditionally, has never been true. They were always either doing starnge shifts like 24 hours twice then 2 free days, repeat or working way more than 5 days a week, based on demand (which of course has been increasing since businesses hire less and less for some fuckin reason).
Major 4-day workweek study suggests that when we work 5 days we spend one doing basically nothing ( www.msn.com )