Time to launch a consulting startup and promise a 20% increase in productivity

Lacking the grindset there - my consulting startup offers a 75% increase in productivity, via a 7 day a week schedule at the daily output shown in this trial.

You can trebble that if you dont let the employees sleep or eat as well, for details you would have to sign up for the platinum package.

Is a package available where employees are taught that "unions" are where you formally marry the company?

This assumes an awful lot about the type of work done. Many jobs are about being present between certain given hours.

Good luck getting 5 days work out of a nurse in 4 days.

I agree with your point, but it is very common for clinical staff to work 12 hour shifts and do 3 or 4 per week.

That's easy, obviously the patients will be moved to a 4-day-week as well, and adjust their recuperation accordingly.

Which is, of course, why a trial of self selecting companies mostly in the knowledge work sector dropping down to 0.8FTE doesn't tell very much about the rest of the world

Basically jobs where the person is providing real time services, whether flipping burgers or providing technical support, etc.