What’s your opinion on a 4 day work week?

A friend of mine, we call him lucky git, works for a company that trialled and kept the four day working week. It's 100% pay, 80% hours. The staff had the option of missing Wednesday or Friday. Almost all opted for Friday but they had a mix in the trial group. The guys who took Wednesday off, although it was reported that there was an improvement in terms of performance, the highest performers were the Friday-off contingent. Since the last year or more, the company works Monday-Thursday with only a skeleton staff around on Friday to deal with customers and are paid overtime commensurate with the extra half days. Overall, performance has improved. The measures they used were output for their development and production staff, sales work an equivalent four-day week but the day is moveable or they can elect to give it up should they want to visit a particularly interesting client, the company has reported a total of three sick days across the entire employee base of approximately 200 since going to WFH / 4 days per week, only certain departments are required to be in-office (and it's where all three sick days occurred), to the point that they have let go of leases on three floors of the building they are in and only have a single floor now made up of half hot desks and perm desks and they struggle to fill that most days. Overall, the profits to the company have skyrocketed, people are happier with the vastly improved work/life balance, it's a complete success story. They are even looking how to convert the people in office into work from home types. The reasons they are in office is largely as their roles call for it and a handful who prefer the office as opposed to working from home. I often get emails from him about the cool stuff he gets up to. His fitness is much better, he says that he now has time to help kids with their homework tasks, he's started playing guitar in a band again, he sometimes takes the wife and kids off for a cheeky weekend away and has the actual time to recover from it, life quality has all very much improved all round. And while it sounds weird, to me his teeth look better. I can't quite explain it, but they are. To me, given that huge measure of success so personally close to me it seems insane that the UK are not doing this. This is just one company who have embraced the change whole heartedly and it's working for them. I floated this once with my board during a management meeting and was practically laughed out of the room. Some leopards will never change their spots. I was told my platitude was circumstantial at best and likely untrue. Meh, what can you say to that. I have told him next time there is a vacancy, even non management, put me up. Though I have been managing teams for my last four roles, I couldn't give a monkeys about reverting to a grunt if it meant that sort of benefits package. I have a feeling it will never be rolled out country-wide. There are too many haves and have nots as well as old school attitudes towards it all. It is a shame, but only the most progressive and forward thinking organisations will at least trial if not adopt the change.