> Naive question but if it works best wouldn't companies that have a four day work week outperform theirs peers and because of that grow faster, and become more common?

Eventually, but what's the typical lifecycle of a company? And if e.g. Treehouse succeeds or fails, was that because of their 4 day work week or because of any of the hundreds of other reasons a company might succeed or fail?

In a perfect free market, like a spherical chicken in a vacuum. Maybe.

Problem is there's no such thing, monopoly powers, government subsidies, inter-company issues, contracts.

All these things can mean that a less functional, more wasteful and less productive organisation performs (in the sense of the metric that companies care about , line go up) better than a 4 day week startup.

In what metric do they get ahead? I think this is the key. What many visualise as getting ahead primarily seems to be fund raising or having a higher monetary value. Especially in startups where the largest mouth, the biggest blagger, or the quickest to mention a buzz word gets you more funding. Being closer to your end goal, with an adoptable product that improves society, is really the only metric that matters.

Think of it like a sprint versus a marathon. If you run at full speed you can get farther than someone keeping a steady pace in the same amount of time, but you’re going to tire yourself out and become slower. You’ll lose in the long run despite looking very “productive” at the start.

Similarly, have you ever been “in the zone” and worked non-stop on a fun project, being super-productive for a full week or even multiple weeks, but then “crashed” (or even burned out) and your output got worse?

New companies are on a race against the clock. At the beginning everything is a cost, you’re constantly losing money. So you plough through to survive until you become stable. Then you need to scale back and take it slower to allow yourself to recuperate and keep going.

Also, keep in mind that small companies can often be very productive simply by having fewer employees and “red tape”. You can have an idea, send a message to someone else, get an immediate OK and get going. When a company gets too big and has lots of processes to keep things running, a lot of effort is wasted on even getting started.